Top 200 General Science Questions
Two hundred general science questions with answers and explanations.
200 questions. Each answer is hidden until you open it.
- Q1EasyUnits and Measurement
What is the SI unit of force?
- aNewton
- bJoule
- cWatt
- dPascal
Show the answer
Answer: a — Newton
Force is measured in newtons, defined as the force that gives a one kilogram mass an acceleration of one metre per second squared. The joule measures energy and the watt power.
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- Q2MediumUnits and Measurement
What is the SI unit of electric current?
- aVolt
- bOhm
- cCoulomb
- dAmpere
Show the answer
Answer: d — Ampere
Current is measured in amperes. The volt measures potential difference, the ohm resistance and the coulomb quantity of charge.
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- Q3EasyMotion and Force
Newton's first law of motion is also known by which name?
- aLaw of momentum
- bLaw of gravitation
- cLaw of conservation
- dLaw of inertia
Show the answer
Answer: d — Law of inertia
The first law says a body stays at rest or in uniform motion unless a force acts on it, which is the property called inertia.
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- Q4MediumMotion and Force
A physical quantity having both magnitude and direction is called a:
- aVector quantity
- bScalar quantity
- cDerived quantity
- dFundamental quantity
Show the answer
Answer: a — Vector quantity
Velocity and force are vectors because direction matters. Speed and mass are scalars, having magnitude only.
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- Q5MediumMotion and Force
The rate of change of displacement with time is called:
- aSpeed
- bAcceleration
- cVelocity
- dMomentum
Show the answer
Answer: c — Velocity
Velocity is displacement per unit time and carries a direction. Speed is distance per unit time and has none, and acceleration is the rate of change of velocity.
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- Q6HardMotion and Force
The momentum of a moving body is the product of which two quantities?
- aForce and time
- bMass and velocity
- cMass and acceleration
- dForce and distance
Show the answer
Answer: b — Mass and velocity
Momentum is mass times velocity. Force times time gives impulse and force times distance gives work, so the three are easily confused.
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- Q7MediumLight and Optics
Which type of mirror is used as the side or wing mirror of a vehicle?
- aConcave mirror
- bPlane mirror
- cConvex mirror
- dParabolic mirror
Show the answer
Answer: c — Convex mirror
A convex mirror always gives an upright, diminished image over a wide field of view, which is what a driver needs alongside the vehicle.
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- Q8MediumLight and Optics
The splitting of white light into its constituent colours is called:
- aDispersion
- bReflection
- cDiffraction
- dPolarisation
Show the answer
Answer: a — Dispersion
Different colours bend by different amounts in glass, so a prism spreads white light into a spectrum. The same effect in raindrops produces a rainbow.
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- Q9MediumLight and Optics
Which type of lens is used to correct short-sightedness?
- aConcave lens
- bConvex lens
- cCylindrical lens
- dBifocal lens
Show the answer
Answer: a — Concave lens
In myopia the image forms in front of the retina, so a diverging concave lens is needed. Long-sightedness is corrected with a convex lens instead.
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- Q10MediumSound and Waves
Sound travels fastest through which of the following?
- aAir
- bWater
- cSteel
- dWood
Show the answer
Answer: c — Steel
Sound moves fastest through solids because their particles are packed closest, and slowest through gases. In steel it travels roughly fifteen times faster than in air.
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- Q11MediumSound and Waves
The number of vibrations produced per second by a wave is called its:
- aAmplitude
- bFrequency
- cWavelength
- dSpeed
Show the answer
Answer: b — Frequency
Frequency is measured in hertz and decides the pitch of a sound. Amplitude decides loudness and wavelength is the distance between two crests.
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- Q12MediumHeat and Thermodynamics
The normal temperature of the human body is approximately:
- a37 degrees Celsius
- b32 degrees Celsius
- c40 degrees Celsius
- d27 degrees Celsius
Show the answer
Answer: a — 37 degrees Celsius
Normal body temperature is about 37 degrees Celsius, which is 98.6 degrees Fahrenheit.
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- Q13MediumHeat and Thermodynamics
Heat transfer in liquids and gases by the actual movement of particles is called:
- aConduction
- bRadiation
- cDiffusion
- dConvection
Show the answer
Answer: d — Convection
Warmer fluid rises and cooler fluid sinks, carrying heat with it. Conduction passes heat through a solid and radiation needs no medium at all.
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- Q14MediumElectricity and Magnetism
Which alloy is commonly used for the heating element of an electric iron?
- aBrass
- bBronze
- cSolder
- dNichrome
Show the answer
Answer: d — Nichrome
Nichrome has high resistance and does not oxidise easily when red hot. Brass, bronze and solder all melt or corrode long before reaching that temperature.
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- Q15MediumElectricity and Magnetism
Which instrument is used to measure electric current in a circuit?
- aVoltmeter
- bAmmeter
- cPotentiometer
- dWattmeter
Show the answer
Answer: b — Ammeter
An ammeter is wired in series to measure current. A voltmeter and potentiometer measure potential difference, and a wattmeter measures power.
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- Q16MediumAtomic Structure
Which subatomic particle carries no electric charge?
- aProton
- bElectron
- cPositron
- dNeutron
Show the answer
Answer: d — Neutron
The neutron is electrically neutral and sits in the nucleus alongside the positively charged proton. Electrons carry a negative charge.
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- Q17MediumAtomic Structure
The atomic number of an element is equal to the number of:
- aNeutrons in its nucleus
- bProtons and neutrons together
- cProtons in its nucleus
- dElectron shells it has
Show the answer
Answer: c — Protons in its nucleus
Atomic number counts protons and fixes which element it is. Protons and neutrons together give the mass number instead.
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- Q18EasyPeriodic Table and Elements
Which is the lightest element in the periodic table?
- aHelium
- bLithium
- cCarbon
- dHydrogen
Show the answer
Answer: d — Hydrogen
Hydrogen has one proton and one electron, making it the lightest element and the most abundant in the universe.
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- Q19MediumPeriodic Table and Elements
What is the chemical symbol of gold?
- aAu
- bAg
- cFe
- dPb
Show the answer
Answer: a — Au
Gold takes Au from the Latin aurum. Ag is silver from argentum, Fe iron from ferrum and Pb lead from plumbum, so all four come from Latin.
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- Q20MediumPeriodic Table and Elements
Which gas is present in the largest proportion in the Earth's atmosphere?
- aOxygen
- bCarbon dioxide
- cNitrogen
- dArgon
Show the answer
Answer: c — Nitrogen
Nitrogen makes up about 78 per cent of the atmosphere and oxygen about 21 per cent, leaving argon and carbon dioxide as minor components.
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- Q21EasyAcids Bases and Salts
What is the pH value of a neutral solution?
- a0
- b7
- c14
- d1
Show the answer
Answer: b — 7
Pure water has a pH of 7. Values below 7 are acidic and those above are basic, on a scale running from 0 to 14.
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- Q22EasyAcids Bases and Salts
Blue litmus paper turns which colour when dipped in an acid?
- aGreen
- bRed
- cYellow
- dColourless
Show the answer
Answer: b — Red
Acids turn blue litmus red, while bases turn red litmus blue. That pair of changes is the standard laboratory test.
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- Q23MediumAcids Bases and Salts
Sodium bicarbonate is commonly known by which name?
- aWashing soda
- bCaustic soda
- cBleaching powder
- dBaking soda
Show the answer
Answer: d — Baking soda
Sodium bicarbonate is baking soda. Washing soda is sodium carbonate and caustic soda is sodium hydroxide, so the three are easily confused.
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- Q24EasyMetals and Non-metals
Which metal is in liquid state at ordinary room temperature?
- aMercury
- bSodium
- cLead
- dZinc
Show the answer
Answer: a — Mercury
Mercury is the only metal that is liquid at room temperature, which is why it was long used in thermometers and barometers.
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- Q25HardMetals and Non-metals
Which is the most abundant metal in the Earth's crust?
- aAluminium
- bIron
- cCopper
- dCalcium
Show the answer
Answer: a — Aluminium
Aluminium is the most abundant metal in the crust and iron the second. Oxygen and silicon are the most abundant elements overall.
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- Q26EasyCarbon and Organic Chemistry
Which is the hardest naturally occurring substance?
- aQuartz
- bDiamond
- cGraphite
- dCorundum
Show the answer
Answer: b — Diamond
Diamond is the hardest natural substance. It is a form of carbon, as is graphite, which is one of the softest, the difference lying in how the atoms are bonded.
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- Q27MediumCarbon and Organic Chemistry
What is the chemical formula of methane?
- aC2H6
- bCO2
- cCH4
- dC2H4
Show the answer
Answer: c — CH4
Methane is the simplest hydrocarbon, one carbon atom bonded to four hydrogen atoms. It is the main constituent of natural gas and biogas.
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- Q28EasyEveryday Chemistry
Common salt is chemically known as:
- aSodium carbonate
- bSodium chloride
- cCalcium chloride
- dPotassium chloride
Show the answer
Answer: b — Sodium chloride
Table salt is sodium chloride. Sodium carbonate is washing soda and potassium chloride is used as a salt substitute in some diets.
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- Q29EasyEveryday Chemistry
Which gas is commonly used in fire extinguishers?
- aCarbon dioxide
- bOxygen
- cHydrogen
- dNitrogen
Show the answer
Answer: a — Carbon dioxide
Carbon dioxide is heavier than air and does not support burning, so it smothers a fire by cutting off oxygen.
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- Q30MediumEveryday Chemistry
Vinegar is a dilute solution of which acid?
- aCitric acid
- bLactic acid
- cAcetic acid
- dTartaric acid
Show the answer
Answer: c — Acetic acid
Vinegar is roughly five per cent acetic acid. Citric acid is found in lemons, lactic acid in sour milk and tartaric acid in tamarind.
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- Q31EasyCell Biology
Which organelle is known as the powerhouse of the cell?
- aRibosome
- bGolgi body
- cMitochondria
- dLysosome
Show the answer
Answer: c — Mitochondria
Mitochondria release energy from food as ATP. Ribosomes build proteins and lysosomes break down waste inside the cell.
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- Q32MediumCell Biology
Which part of the cell controls all its activities?
- aCytoplasm
- bCell membrane
- cVacuole
- dNucleus
Show the answer
Answer: d — Nucleus
The nucleus holds the genetic material and directs the cell, which is why it is called the control centre. The membrane only regulates what enters and leaves.
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- Q33EasyHuman Body Systems
Which is the largest organ of the human body by surface area and weight?
- aLiver
- bSkin
- cBrain
- dLungs
Show the answer
Answer: b — Skin
The skin is the largest organ of the human body by surface area and overall weight. The liver is the largest internal organ.
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- Q34MediumHuman Body Systems
How many bones are there in the body of an adult human?
- a206
- b300
- c186
- d256
Show the answer
Answer: a — 206
An adult has 206 bones. A newborn has about 300, several of which fuse together during growth.
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- Q35MediumHuman Body Systems
What is the functional filtering unit of the kidney called?
- aNephron
- bNeuron
- cAlveolus
- dVillus
Show the answer
Answer: a — Nephron
Each kidney holds about a million nephrons, which filter blood and form urine. A neuron is a nerve cell and an alveolus an air sac in the lung.
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- Q36HardHuman Body Systems
Which blood group is described as the universal donor for red blood cell transfusion?
- aAB positive
- bA positive
- cO negative
- dB negative
Show the answer
Answer: c — O negative
O negative red cells carry neither A nor B antigens nor the Rh factor, so they can be given to any recipient. AB positive is the universal recipient.
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- Q37HardHuman Body Systems
Which gland is known as the master gland of the human body?
- aPituitary gland
- bThyroid gland
- cAdrenal gland
- dPancreas
Show the answer
Answer: a — Pituitary gland
The pituitary controls the output of several other endocrine glands, which is why it is called the master gland despite its small size.
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- Q38EasyNutrition and Vitamins
Deficiency of vitamin C causes which disease?
- aRickets
- bScurvy
- cBeriberi
- dPellagra
Show the answer
Answer: b — Scurvy
Scurvy comes from a lack of vitamin C and causes bleeding gums. Rickets follows a lack of vitamin D and beriberi a lack of vitamin B1.
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- Q39MediumNutrition and Vitamins
Which vitamin is produced in human skin on exposure to sunlight?
- aVitamin A
- bVitamin C
- cVitamin K
- dVitamin D
Show the answer
Answer: d — Vitamin D
Sunlight lets the skin make vitamin D, which the body needs to absorb calcium. A shortage of it causes rickets in children.
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- Q40MediumNutrition and Vitamins
Haemoglobin, the oxygen-carrying pigment of blood, contains which metal?
- aCalcium
- bMagnesium
- cIron
- dZinc
Show the answer
Answer: c — Iron
Iron sits at the centre of haemoglobin and binds oxygen, which is why a shortage of iron leads to anaemia. Chlorophyll uses magnesium in the same structural role.
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- Q41EasyDiseases and Pathogens
Malaria is transmitted to humans by the bite of which mosquito?
- aMale Anopheles mosquito
- bAedes mosquito
- cHousefly
- dFemale Anopheles mosquito
Show the answer
Answer: d — Female Anopheles mosquito
Malaria is transmitted through the bite of an infected female Anopheles mosquito. The parasite belongs to the genus Plasmodium.
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- Q42MediumDiseases and Pathogens
Jaundice is a condition that primarily affects which organ?
- aKidney
- bLiver
- cHeart
- dLungs
Show the answer
Answer: b — Liver
Jaundice follows when the liver cannot clear bilirubin from the blood, which is what turns the skin and eyes yellow.
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- Q43MediumDiseases and Pathogens
Tuberculosis in humans is caused by which kind of organism?
- aVirus
- bFungus
- cProtozoan
- dBacterium
Show the answer
Answer: d — Bacterium
Tuberculosis is caused by the bacterium Mycobacterium tuberculosis and mainly attacks the lungs, which is why it responds to antibiotics.
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- Q44EasyPlant Biology
Which pigment gives green colour to the leaves of plants?
- aHaemoglobin
- bCarotene
- cMelanin
- dChlorophyll
Show the answer
Answer: d — Chlorophyll
Chlorophyll absorbs red and blue light and reflects green, which is why leaves look green. It is also what captures light energy for photosynthesis.
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- Q45EasyPlant Biology
The process by which green plants prepare their own food is called:
- aRespiration
- bTranspiration
- cPhotosynthesis
- dGermination
Show the answer
Answer: c — Photosynthesis
Photosynthesis uses sunlight, carbon dioxide and water to make glucose and release oxygen. Respiration is the reverse process, releasing energy from food.
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- Q46HardPlant Biology
Which tissue carries water and minerals from the roots to the leaves of a plant?
- aPhloem
- bXylem
- cCambium
- dEpidermis
Show the answer
Answer: b — Xylem
Xylem carries water upward from the roots. Phloem moves the food made in the leaves to the rest of the plant, so the two run in opposite directions.
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- Q47MediumScience and Technology
The DNA molecule has which structural shape?
- aDouble helix
- bSingle helix
- cTriple helix
- dCircular closed loop
Show the answer
Answer: a — Double helix
Watson and Crick showed in 1953 that DNA is a double helix. Some bacterial DNA is a circular loop, but the loop itself is still a double helix.
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- Q48EasyScience and Technology
Which instrument is used to measure atmospheric pressure?
- aThermometer
- bHygrometer
- cBarometer
- dAnemometer
Show the answer
Answer: c — Barometer
A barometer measures atmospheric pressure and a falling reading warns of a storm. A hygrometer measures humidity and an anemometer wind speed.
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- Q49EasyScience and Technology
The Richter scale is traditionally used to express which property of an earthquake?
- aThe intensity of rainfall
- bThe magnitude of earthquakes
- cThe speed of wind
- dThe depth of the ocean
Show the answer
Answer: b — The magnitude of earthquakes
The Richter scale is a logarithmic magnitude scale developed to quantify earthquake magnitude. Modern seismology commonly uses moment magnitude (Mw) for large earthquakes.
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- Q50EasyScience and Technology
Which device converts sound energy into electrical energy?
- aLoudspeaker
- bDynamo
- cMicrophone
- dTransformer
Show the answer
Answer: c — Microphone
A microphone turns sound into an electrical signal. A loudspeaker does the reverse, and a dynamo converts mechanical energy into electrical energy.
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- Q51EasyUnits and Measurement
What is the SI unit of power?
- aWatt
- bJoule
- cNewton
- dPascal
Show the answer
Answer: a — Watt
Power is the rate of doing work and is measured in watts, where one watt is one joule per second.
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- Q52EasyUnits and Measurement
What is the SI unit of work and energy?
- aWatt
- bNewton
- cAmpere
- dJoule
Show the answer
Answer: d — Joule
Work and energy share the joule as their unit, one joule being the work done when a force of one newton moves a body one metre.
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- Q53EasyMotion and Force
The acceleration due to gravity on the surface of the Earth is approximately:
- a6.7 metres per second squared
- b3.7 metres per second squared
- c11.2 metres per second squared
- d9.8 metres per second squared
Show the answer
Answer: d — 9.8 metres per second squared
Free fall near the surface accelerates a body at about 9.8 metres per second squared. The figure 11.2 kilometres per second is the escape velocity instead.
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- Q54MediumMotion and Force
Which law of motion states that every action has an equal and opposite reaction?
- aNewton's third law
- bNewton's first law
- cNewton's second law
- dNewton's law of gravitation
Show the answer
Answer: a — Newton's third law
The third law explains the recoil of a gun and the way a rocket is driven forward by the gases it expels backwards.
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- Q55MediumMotion and Force
A body moving along a circular path at constant speed has which of the following?
- aZero acceleration throughout
- bA constant velocity
- cA continuously changing velocity
- dNo force acting on it
Show the answer
Answer: c — A continuously changing velocity
Velocity includes direction, and the direction changes at every point of a circle. That change is what the centripetal force produces.
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- Q56HardMotion and Force
The product of a force and the time for which it acts is called:
- aMomentum
- bImpulse
- cWork
- dPower
Show the answer
Answer: b — Impulse
Impulse equals force times time and also equals the change in momentum it produces. Work is force times distance instead.
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- Q57MediumLight and Optics
The speed of light in a vacuum is approximately:
- a3 lakh metres per second
- b3 thousand kilometres per second
- c3 lakh kilometres per second
- d30 lakh kilometres per second
Show the answer
Answer: c — 3 lakh kilometres per second
The speed of light in vacuum is approximately 3 × 10^8 metres per second, or 300,000 kilometres per second.
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- Q58EasyLight and Optics
Which colour of visible light has the longest wavelength?
- aRed
- bViolet
- cGreen
- dBlue
Show the answer
Answer: a — Red
Red has the longest wavelength and violet the shortest. That is why red light scatters least and is used for danger signals seen from far off.
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- Q59HardLight and Optics
Which phenomenon allows an optical fibre to carry light along its length?
- aTotal internal reflection
- bRefraction
- cDiffraction
- dInterference
Show the answer
Answer: a — Total internal reflection
Light striking the wall beyond the critical angle is reflected entirely back inside, so it travels the length of the fibre with little loss.
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- Q60EasySound and Waves
The approximate audible frequency range of a normal human ear is:
- a2 Hz to 2000 Hz
- b200 Hz to 200000 Hz
- c20 Hz to 20000 Hz
- d20 Hz to 2000 Hz
Show the answer
Answer: c — 20 Hz to 20000 Hz
A commonly used approximate audible range for humans is 20 Hz to 20,000 Hz. The actual range varies with age and individual hearing.
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- Q61EasySound and Waves
An echo is produced by which behaviour of sound?
- aRefraction
- bReflection
- cAbsorption
- dDiffraction
Show the answer
Answer: b — Reflection
Sound bounces off a distant surface and returns to the listener. The delay must exceed about a tenth of a second for the ear to hear it separately.
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- Q62EasyHeat and Thermodynamics
At normal atmospheric pressure, water boils at which temperature?
- a100 degrees Celsius
- b90 degrees Celsius
- c120 degrees Celsius
- d80 degrees Celsius
Show the answer
Answer: a — 100 degrees Celsius
Water boils at 100 degrees Celsius at sea level. On a mountain the lower pressure makes it boil below that, which is why cooking takes longer there.
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- Q63MediumHeat and Thermodynamics
The direct change of a solid into a gas without passing through the liquid state is called:
- aEvaporation
- bCondensation
- cFusion
- dSublimation
Show the answer
Answer: d — Sublimation
Camphor and dry ice sublime. Fusion is melting and condensation is the change from gas back to liquid.
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- Q64MediumElectricity and Magnetism
According to Ohm's law, multiplying current by resistance gives which quantity?
- aPower
- bCharge
- cCapacitance
- dPotential difference
Show the answer
Answer: d — Potential difference
Ohm's law states that potential difference equals current times resistance, provided the temperature stays constant.
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- Q65MediumElectricity and Magnetism
An electric bulb glows because current passing through the filament produces which effect?
- aMagnetic effect
- bHeating effect
- cChemical effect
- dInductive effect
Show the answer
Answer: b — Heating effect
Resistance turns electrical energy into heat, and a tungsten filament grows hot enough to glow white. The magnetic effect is what drives a motor instead.
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- Q66MediumAtomic Structure
Isotopes of an element have the same number of which particle?
- aNeutrons
- bNucleons
- cAlpha particles
- dProtons
Show the answer
Answer: d — Protons
Isotopes share the proton count, so they are the same element, but differ in neutrons and therefore in mass number.
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- Q67HardAtomic Structure
Who discovered the electron?
- aErnest Rutherford
- bJames Chadwick
- cJ. J. Thomson
- dNiels Bohr
Show the answer
Answer: c — J. J. Thomson
Thomson identified the electron in 1897. Rutherford later found the proton and nucleus, and Chadwick the neutron.
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- Q68EasyPeriodic Table and Elements
What is the chemical symbol of sodium?
- aSo
- bSn
- cSd
- dNa
Show the answer
Answer: d — Na
Sodium takes Na from its Latin name natrium. Sn is tin, from stannum, so several symbols come from Latin rather than English.
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- Q69MediumPeriodic Table and Elements
Which is the most abundant element in the Earth's crust by mass?
- aOxygen
- bSilicon
- cAluminium
- dIron
Show the answer
Answer: a — Oxygen
Oxygen is the most abundant element in Earth's crust by mass, followed by silicon. Aluminium is the most abundant metal in the crust.
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- Q70MediumPeriodic Table and Elements
Which noble gas is commonly associated with red-orange light in advertising signs?
- aArgon
- bHelium
- cNeon
- dKrypton
Show the answer
Answer: c — Neon
Neon gas produces a characteristic red-orange glow in discharge tubes. Different gases can produce different colours.
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- Q71EasyAcids Bases and Salts
Which acid is present in the human stomach and aids digestion?
- aSulphuric acid
- bHydrochloric acid
- cNitric acid
- dCarbonic acid
Show the answer
Answer: b — Hydrochloric acid
Gastric juice contains dilute hydrochloric acid, which activates digestive enzymes and kills many swallowed microbes.
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- Q72MediumAcids Bases and Salts
Which chemical is used along with fat in the manufacture of soap?
- aSodium chloride
- bSodium hydroxide
- cCalcium carbonate
- dAmmonium nitrate
Show the answer
Answer: b — Sodium hydroxide
Sodium hydroxide, a strong alkali, splits fat into soap and glycerol. Sodium chloride is added later only to separate the soap out.
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- Q73MediumMetals and Non-metals
Which metal is the best conductor of electricity?
- aCopper
- bGold
- cAluminium
- dSilver
Show the answer
Answer: d — Silver
Silver conducts best of all metals, with copper close behind. Copper is used for wiring because it costs far less.
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- Q74MediumMetals and Non-metals
Rusting of iron requires the presence of which two things?
- aOxygen and moisture
- bNitrogen and heat
- cCarbon dioxide and light
- dHydrogen and pressure
Show the answer
Answer: a — Oxygen and moisture
Rust is hydrated iron oxide, so both air and water must be present. Painting or greasing works by keeping the two away from the metal.
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- Q75MediumMetals and Non-metals
Brass is an alloy of which two metals?
- aCopper and zinc
- bCopper and tin
- cIron and carbon
- dAluminium and copper
Show the answer
Answer: a — Copper and zinc
Brass is copper with zinc, while bronze is copper with tin. Steel is the alloy of iron with carbon.
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- Q76MediumCarbon and Organic Chemistry
Which allotrope of carbon is used as a lubricant?
- aDiamond
- bGraphite
- cFullerene
- dCharcoal
Show the answer
Answer: b — Graphite
Graphite is built from sheets that slide over one another, which makes it slippery. Diamond, the other common allotrope, is the hardest natural substance.
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- Q77MediumCarbon and Organic Chemistry
Which poisonous gas is produced by the incomplete combustion of fuel?
- aCarbon dioxide
- bNitrogen
- cCarbon monoxide
- dMethane
Show the answer
Answer: c — Carbon monoxide
Incomplete burning yields carbon monoxide, which binds to haemoglobin far more tightly than oxygen does and starves the body of it.
Source: Static General Science — competitive exam topic
- Q78EasyEveryday Chemistry
Which acid gives lemons and oranges their sour taste?
- aAcetic acid
- bCitric acid
- cLactic acid
- dOxalic acid
Show the answer
Answer: b — Citric acid
Citrus fruits contain citric acid. Acetic acid is in vinegar, lactic acid in curd and oxalic acid in spinach and tomatoes.
Source: Static General Science — competitive exam topic
- Q79MediumEveryday Chemistry
Liquefied petroleum gas used for cooking consists mainly of which gases?
- aButane and propane
- bMethane and ethane
- cHydrogen and oxygen
- dNitrogen and argon
Show the answer
Answer: a — Butane and propane
LPG is mostly butane with some propane, both easily liquefied under moderate pressure. Piped natural gas is mostly methane instead.
Source: Static General Science — competitive exam topic
- Q80MediumEveryday Chemistry
Which chemical is commonly used to disinfect drinking water?
- aNitrogen
- bSodium chloride
- cChlorine
- dCalcium carbonate
Show the answer
Answer: c — Chlorine
Chlorine kills bacteria and stays active in the pipeline, which is why municipal supplies are chlorinated rather than merely filtered.
Source: Static General Science — competitive exam topic
- Q81EasyCell Biology
A rigid cell wall outside the cell membrane is found in which type of cell?
- aAnimal cell
- bHuman nerve cell
- cRed blood cell
- dPlant cell
Show the answer
Answer: d — Plant cell
Plant cells have a cellulose wall that gives them a fixed shape and support. Animal cells have only a flexible membrane.
Source: Static General Science — competitive exam topic
- Q82MediumCell Biology
Who first observed and named cells while examining a thin slice of cork?
- aRobert Brown
- bAnton van Leeuwenhoek
- cTheodor Schwann
- dRobert Hooke
Show the answer
Answer: d — Robert Hooke
Hooke saw box-like compartments in cork in 1665 and called them cells. Leeuwenhoek was the first to see living cells, and Brown identified the nucleus.
Source: Static General Science — competitive exam topic
- Q83EasyHuman Body Systems
How many chambers does the human heart have?
- aTwo
- bFour
- cThree
- dSix
Show the answer
Answer: b — Four
Two atria receive blood and two ventricles pump it out. The four-chambered design keeps oxygenated and deoxygenated blood completely separate.
Source: Static General Science — competitive exam topic
- Q84MediumHuman Body Systems
Which is the longest bone in the human body?
- aFemur
- bHumerus
- cTibia
- dFibula
Show the answer
Answer: a — Femur
The femur, or thigh bone, is the longest and strongest bone. The stapes in the ear is the smallest.
Source: Static General Science — competitive exam topic
- Q85MediumHuman Body Systems
Insulin is produced by which organ of the human body?
- aLiver
- bPancreas
- cKidney
- dThyroid
Show the answer
Answer: b — Pancreas
The pancreas secretes insulin, which lowers blood glucose. Diabetes follows when too little is produced or the body cannot use it.
Source: Static General Science — competitive exam topic
- Q86HardHuman Body Systems
Which part of the brain controls balance and coordination of movement?
- aCerebellum
- bCerebrum
- cMedulla oblongata
- dHypothalamus
Show the answer
Answer: a — Cerebellum
The cerebellum coordinates posture and balance. The cerebrum handles thought and memory, and the medulla controls breathing and heartbeat.
Source: Static General Science — competitive exam topic
- Q87MediumHuman Body Systems
How many chromosomes are normally present in a human somatic (body) cell?
- a23
- b48
- c46
- d44
Show the answer
Answer: c — 46
Most human somatic cells contain 46 chromosomes arranged in 23 pairs. Mature sperm and egg cells normally contain 23 chromosomes.
Source: Static General Science — competitive exam topic
- Q88EasyNutrition and Vitamins
Deficiency of iodine in the diet causes which disorder?
- aScurvy
- bGoitre
- cRickets
- dBeriberi
Show the answer
Answer: b — Goitre
The thyroid enlarges when iodine is short, producing goitre. Adding iodine to common salt is the standard public health remedy.
Source: Static General Science — competitive exam topic
- Q89MediumNutrition and Vitamins
Which nutrient provides the greatest amount of energy per gram?
- aCarbohydrate
- bProtein
- cVitamin
- dFat
Show the answer
Answer: d — Fat
Fat yields about nine calories per gram, roughly twice what carbohydrate or protein gives. Vitamins supply no energy at all.
Source: Static General Science — competitive exam topic
- Q90HardNutrition and Vitamins
Which vitamin is essential for the clotting of blood?
- aVitamin C
- bVitamin A
- cVitamin K
- dVitamin E
Show the answer
Answer: c — Vitamin K
Vitamin K is needed to make the proteins that clot blood, so a shortage causes prolonged bleeding from small injuries.
Source: Static General Science — competitive exam topic
- Q91EasyDiseases and Pathogens
Dengue fever is spread by which mosquito?
- aAnopheles
- bCulex
- cMansonia
- dAedes
Show the answer
Answer: d — Aedes
The Aedes mosquito spreads dengue and chikungunya and bites mainly by day. Anopheles carries malaria and Culex carries filariasis.
Source: Static General Science — competitive exam topic
- Q92MediumDiseases and Pathogens
Which of the following diseases is caused by a virus?
- aCholera
- bPolio
- cTyphoid
- dTetanus
Show the answer
Answer: b — Polio
Polio is viral, which is why it is prevented by vaccination rather than treated with antibiotics. Cholera, typhoid and tetanus are all bacterial.
Source: Static General Science — competitive exam topic
- Q93MediumDiseases and Pathogens
Rabies is usually transmitted to humans in which way?
- aThrough contaminated drinking water
- bThrough the bite of a mosquito
- cThrough the air when someone coughs
- dThrough the bite of an infected animal
Show the answer
Answer: d — Through the bite of an infected animal
The rabies virus is carried in the saliva of an infected animal and enters through a bite. Prompt vaccination after exposure prevents the disease.
Source: Static General Science — competitive exam topic
- Q94EasyPlant Biology
Which part of a plant absorbs water and minerals from the soil?
- aStem
- bLeaf
- cFlower
- dRoot
Show the answer
Answer: d — Root
Root hairs take in water and dissolved minerals, and the stem then carries them upward to the leaves.
Source: Static General Science — competitive exam topic
- Q95EasyPlant Biology
Stomata, the tiny pores for gas exchange, are found mainly on which plant part?
- aRoots
- bWoody stems
- cLeaves
- dSeeds
Show the answer
Answer: c — Leaves
Stomata sit mostly on the underside of leaves and are opened and closed by guard cells, controlling both gas exchange and water loss.
Source: Static General Science — competitive exam topic
- Q96EasyPlant Biology
Which instrument is used to measure atmospheric pressure?
- aCarbon dioxide
- bOxygen
- cNitrogen
- dHydrogen
Show the answer
Answer: b — Oxygen
A barometer measures atmospheric pressure. A mercury barometer and aneroid barometer are common types.
Source: Static General Science — competitive exam topic
- Q97MediumScience and Technology
In the term LASER, what does the letter A stand for?
- aAmplification
- bAbsorption
- cAcceleration
- dAlignment
Show the answer
Answer: a — Amplification
LASER stands for Light Amplification by Stimulated Emission of Radiation, so the beam is light that has been amplified rather than merely focused.
Source: Static General Science — competitive exam topic
- Q98MediumScience and Technology
Which instrument is used to measure the humidity of air?
- aBarometer
- bLactometer
- cHygrometer
- dSeismograph
Show the answer
Answer: c — Hygrometer
A hygrometer measures moisture in the air. A lactometer checks the purity of milk and a seismograph records earth tremors.
Source: Static General Science — competitive exam topic
- Q99EasyScience and Technology
The theory of relativity was propounded by which scientist?
- aIsaac Newton
- bAlbert Einstein
- cGalileo Galilei
- dMax Planck
Show the answer
Answer: b — Albert Einstein
Einstein published the special theory in 1905 and the general theory in 1915. Max Planck is remembered instead for founding quantum theory.
Source: Static General Science — competitive exam topic
- Q100EasyScience and Technology
What was the name of India's first satellite?
- aBhaskara
- bRohini
- cAryabhata
- dINSAT-1A
Show the answer
Answer: c — Aryabhata
Aryabhata was India's first satellite. It was launched on 19 April 1975 from the Soviet Union with Soviet assistance.
Source: Static General Science — competitive exam topic
- Q101EasyUnits and Measurement
What is the SI unit of temperature?
- aKelvin
- bCelsius
- cFahrenheit
- dRankine
Show the answer
Answer: a — Kelvin
The kelvin is the SI unit and starts at absolute zero. Celsius, Fahrenheit and Rankine are all temperature scales but none is the SI unit.
Source: Static General Science — competitive exam topic
- Q102MediumUnits and Measurement
Pressure is measured in which SI unit?
- aNewton
- bJoule
- cHertz
- dPascal
Show the answer
Answer: d — Pascal
One pascal is one newton spread over one square metre. Atmospheric pressure at sea level is about 101325 pascals.
Source: Static General Science — competitive exam topic
- Q103EasyMotion and Force
The force that opposes relative motion between two surfaces in contact is called:
- aGravity
- bTension
- cThrust
- dFriction
Show the answer
Answer: d — Friction
Friction acts along the surfaces and against the direction of motion. It wastes energy as heat but is also what lets us walk and brake.
Source: Static General Science — competitive exam topic
- Q104MediumMotion and Force
The escape velocity from the surface of the Earth is approximately:
- a11.2 kilometres per second
- b9.8 kilometres per second
- c7.9 kilometres per second
- d3.0 kilometres per second
Show the answer
Answer: a — 11.2 kilometres per second
A body must reach about 11.2 kilometres per second to break free of Earth's gravity. The figure 7.9 is the speed needed for a low orbit instead.
Source: Static General Science — competitive exam topic
- Q105MediumMotion and Force
The weight of a body is greatest at which location on Earth?
- aAt the equator
- bOn a high mountain
- cAt the poles
- dAt the centre of the Earth
Show the answer
Answer: c — At the poles
The Earth bulges at the equator, so the poles are nearer the centre and gravity is slightly stronger there. At the centre the weight would be zero.
Source: Static General Science — competitive exam topic
- Q106HardMotion and Force
The centre of gravity of a uniform metre rod lies at which point?
- aOne of its ends
- bIts midpoint
- cOne quarter along its length
- dOutside the rod
Show the answer
Answer: b — Its midpoint
For a body of uniform density the centre of gravity is at its geometric centre, which is why a uniform rod balances exactly at the middle.
Source: Static General Science — competitive exam topic
- Q107MediumLight and Optics
The twinkling of stars is caused by which phenomenon?
- aTotal internal reflection
- bDispersion of light
- cAtmospheric refraction
- dInterference of light
Show the answer
Answer: c — Atmospheric refraction
Moving layers of air bend starlight by constantly changing amounts, so the star seems to flicker. Planets are nearer and appear as small discs, so they twinkle far less.
Source: Static General Science — competitive exam topic
- Q108EasyLight and Optics
The blue colour of the clear sky is caused by which process?
- aScattering of light
- bReflection of light
- cAbsorption of light
- dPolarisation of light
Show the answer
Answer: a — Scattering of light
Air molecules scatter shorter blue wavelengths far more than red, so blue reaches the eye from all directions. At sunset the light travels further and appears red.
Source: Static General Science — competitive exam topic
- Q109MediumLight and Optics
The image formed on the retina of the human eye is:
- aReal and inverted
- bVirtual and erect
- cReal and erect
- dVirtual and inverted
Show the answer
Answer: a — Real and inverted
The convex eye lens forms a real, inverted image on the retina, and the brain interprets it the right way up.
Source: Static General Science — competitive exam topic
- Q110EasySound and Waves
Sound waves of frequency above the human audible range are called:
- aInfrasonic waves
- bSupersonic waves
- cUltrasonic waves
- dSubsonic waves
Show the answer
Answer: c — Ultrasonic waves
Ultrasonic waves lie above about 20000 hertz. Supersonic and subsonic describe speeds relative to sound rather than frequencies, which is the confusion being tested.
Source: Static General Science — competitive exam topic
- Q111MediumSound and Waves
SONAR is used mainly to determine which of the following?
- aThe height of a mountain
- bThe depth of the sea
- cThe distance of an aircraft in the sky
- dThe speed of ocean currents
Show the answer
Answer: b — The depth of the sea
SONAR sends a pulse through water and times the returning echo. Radar does the same job through air, which is why aircraft are tracked by radar and not by SONAR.
Source: Static General Science — competitive exam topic
- Q112EasyHeat and Thermodynamics
Which mode of heat transfer does not require any material medium?
- aRadiation
- bConduction
- cConvection
- dDiffusion
Show the answer
Answer: a — Radiation
Radiation travels as electromagnetic waves, which is how the Sun's heat crosses the vacuum of space. Conduction and convection both need matter.
Source: Static General Science — competitive exam topic
- Q113MediumHeat and Thermodynamics
Water is used as a coolant in car radiators mainly because it has a high:
- aDensity
- bViscosity
- cSurface tension
- dSpecific heat capacity
Show the answer
Answer: d — Specific heat capacity
Water absorbs a large amount of heat for each degree it warms, so it carries heat away from the engine efficiently.
Source: Static General Science — competitive exam topic
- Q114MediumElectricity and Magnetism
Which device is used to raise or lower an alternating voltage?
- aDynamo
- bRectifier
- cCapacitor
- dTransformer
Show the answer
Answer: d — Transformer
A transformer changes AC voltage by the ratio of turns in its two coils, which is how power is sent at high voltage and used at low voltage.
Source: Static General Science — competitive exam topic
- Q115MediumElectricity and Magnetism
The wire used in an electrical fuse is made of a material having:
- aA very high melting point
- bA low melting point
- cVery low resistance
- dNo resistance at all
Show the answer
Answer: b — A low melting point
A fuse is meant to melt and break the circuit when the current grows too large, so the wire must melt easily and before the appliance is damaged.
Source: Static General Science — competitive exam topic
- Q116MediumAtomic Structure
Who discovered the neutron?
- aJ. J. Thomson
- bErnest Rutherford
- cNiels Bohr
- dJames Chadwick
Show the answer
Answer: d — James Chadwick
Chadwick identified the neutron in 1932, completing the picture of the atom that Thomson and Rutherford had begun.
Source: Static General Science — competitive exam topic
- Q117HardAtomic Structure
What is the maximum number of electrons that the innermost shell of an atom can hold?
- aEight
- bFour
- cTwo
- dEighteen
Show the answer
Answer: c — Two
The K shell holds at most two electrons, following the rule that a shell holds twice the square of its number. The second shell holds eight.
Source: Static General Science — competitive exam topic
- Q118EasyPeriodic Table and Elements
Which instrument is used to detect and record earthquakes?
- aKrypton
- bCalcium
- cCarbon
- dPotassium
Show the answer
Answer: d — Potassium
A seismograph (or seismometer) detects and records ground motion caused by earthquakes. The recorded signal is called a seismogram.
Source: Static General Science — competitive exam topic
- Q119MediumPeriodic Table and Elements
The noble gases are placed in which group of the modern periodic table?
- aGroup 18
- bGroup 1
- cGroup 17
- dGroup 2
Show the answer
Answer: a — Group 18
Group 18 holds helium, neon, argon and the rest. Their outermost shells are full, which is why they hardly react at all.
Source: Static General Science — competitive exam topic
- Q120HardPeriodic Table and Elements
Which non-metal exists as a liquid at ordinary room temperature?
- aIodine
- bSulphur
- cBromine
- dPhosphorus
Show the answer
Answer: c — Bromine
Bromine is the only non-metal that is liquid at room temperature, just as mercury is the only such metal. Iodine and sulphur are solids.
Source: Static General Science — competitive exam topic
- Q121EasyAcids Bases and Salts
Which acid is used in a lead storage battery of a car?
- aHydrochloric acid
- bSulphuric acid
- cNitric acid
- dAcetic acid
Show the answer
Answer: b — Sulphuric acid
A lead acid battery uses dilute sulphuric acid as its electrolyte, which is why the acid is sometimes topped up with distilled water.
Source: Static General Science — competitive exam topic
- Q122MediumAcids Bases and Salts
Milk of magnesia relieves indigestion by doing which of the following?
- aAdding more acid to the stomach
- bNeutralising excess acid in the stomach
- cAbsorbing water from the stomach
- dKilling bacteria in the stomach
Show the answer
Answer: b — Neutralising excess acid in the stomach
Milk of magnesia is magnesium hydroxide, a mild base that neutralises excess hydrochloric acid and raises the pH of the stomach contents.
Source: Static General Science — competitive exam topic
- Q123HardAcids Bases and Salts
Plaster of Paris is obtained by heating which substance?
- aLimestone
- bQuartz
- cBauxite
- dGypsum
Show the answer
Answer: d — Gypsum
Heating gypsum drives off part of its water to give plaster of Paris, which sets hard when water is added again. That is why it is used for casts.
Source: Static General Science — competitive exam topic
- Q124EasyMetals and Non-metals
Which Indian state is known as the 'Land of Festivals'?
- aBauxite
- bHaematite
- cGalena
- dCinnabar
Show the answer
Answer: a — Bauxite
Nagaland is popularly known as the 'Land of Festivals' because of its many traditional festivals. The Hornbill Festival is one of its best-known cultural events.
Source: Static General Science — competitive exam topic
- Q125MediumMetals and Non-metals
Stainless steel is made by alloying iron mainly with which metals?
- aChromium and nickel
- bCopper and zinc
- cManganese and carbon
- dTin and lead
Show the answer
Answer: a — Chromium and nickel
Chromium forms a thin protective oxide layer that stops rusting and nickel adds toughness. Manganese and carbon give ordinary alloy steels instead.
Source: Static General Science — competitive exam topic
- Q126MediumMetals and Non-metals
Galvanisation protects iron by coating it with which metal?
- aTin
- bZinc
- cCopper
- dNickel
Show the answer
Answer: b — Zinc
A zinc layer corrodes in place of the iron beneath it, so the iron stays protected even where the coating is scratched.
Source: Static General Science — competitive exam topic
- Q127MediumCarbon and Organic Chemistry
Which organic compound is present in alcoholic drinks?
- aMethanol
- bGlycerol
- cEthanol
- dAcetone
Show the answer
Answer: c — Ethanol
Drinkable alcohol is ethanol, made by fermenting sugars. Methanol is closely related but severely poisonous, causing blindness or death.
Source: Static General Science — competitive exam topic
- Q128MediumCarbon and Organic Chemistry
PVC, widely used for pipes and cables, stands for which polymer?
- aPolyvinyl carbonate
- bPolyvinyl chloride
- cPolymerised vinyl carbon
- dPhenyl vinyl chloride
Show the answer
Answer: b — Polyvinyl chloride
Polyvinyl chloride is a tough, cheap plastic that resists water and chemicals, which suits it to pipes and cable insulation.
Source: Static General Science — competitive exam topic
- Q129EasyEveryday Chemistry
Nitrous oxide is popularly known by which name?
- aLaughing gas
- bMarsh gas
- cWater gas
- dProducer gas
Show the answer
Answer: a — Laughing gas
Nitrous oxide is called laughing gas and is used as a mild anaesthetic. Marsh gas is methane, which forms in swamps.
Source: Static General Science — competitive exam topic
- Q130MediumEveryday Chemistry
The process of making soap from fat and an alkali is called:
- aFermentation
- bHydrogenation
- cSaponification
- dVulcanisation
Show the answer
Answer: c — Saponification
Saponification splits fat with an alkali to give soap and glycerol. Hydrogenation hardens oils into vanaspati and vulcanisation toughens rubber.
Source: Static General Science — competitive exam topic
- Q131MediumEveryday Chemistry
Bleaching powder is manufactured by passing chlorine over which substance?
- aLimestone
- bGypsum
- cDry slaked lime
- dCommon salt
Show the answer
Answer: c — Dry slaked lime
Chlorine passed over dry slaked lime, which is calcium hydroxide, gives bleaching powder. It is used to whiten cloth and to disinfect water.
Source: Static General Science — competitive exam topic
- Q132EasyCell Biology
Which cell organelle is known as the suicide bag of the cell?
- aRibosome
- bMitochondria
- cGolgi body
- dLysosome
Show the answer
Answer: d — Lysosome
Lysosomes hold digestive enzymes that break down worn-out parts, and can destroy the cell itself when it is damaged.
Source: Static General Science — competitive exam topic
- Q133MediumCell Biology
Which organelle is found in plant cells and carries out photosynthesis?
- aMitochondria
- bChloroplast
- cLysosome
- dCentrosome
Show the answer
Answer: b — Chloroplast
Chloroplasts hold chlorophyll and capture light energy. Mitochondria are present in both plant and animal cells and release energy instead.
Source: Static General Science — competitive exam topic
- Q134EasyHuman Body Systems
Which blood cells gather at the site of a wound to begin the clotting process?
- aPlatelets
- bRed blood cells
- cWhite blood cells
- dLymphocytes
Show the answer
Answer: a — Platelets
Platelets stick together at a wound and trigger the cascade that forms a clot. Red cells carry oxygen and white cells fight infection.
Source: Static General Science — competitive exam topic
- Q135EasyHuman Body Systems
The lens of the human eye is which type of lens?
- aConvex
- bConcave
- cCylindrical
- dPlane
Show the answer
Answer: a — Convex
The eye lens is convex and converges light onto the retina. Muscles change its thickness so that objects at different distances stay in focus.
Source: Static General Science — competitive exam topic
- Q136MediumHuman Body Systems
How many pairs of ribs are there in the human body?
- a10
- b14
- c12
- d11
Show the answer
Answer: c — 12
There are twelve pairs of ribs. The first seven pairs join the breastbone directly and the last two pairs are called floating ribs.
Source: Static General Science — competitive exam topic
- Q137MediumHuman Body Systems
Which is the smallest bone in the human body?
- aStapes
- bMalleus
- cIncus
- dVomer
Show the answer
Answer: a — Stapes
The stapes in the middle ear is the smallest bone. It works with the malleus and incus to pass vibrations to the inner ear.
Source: Static General Science — competitive exam topic
- Q138EasyHuman Body Systems
In the human lungs, the exchange of gases takes place in which structures?
- aBronchi
- bAlveoli
- cTrachea
- dDiaphragm
Show the answer
Answer: b — Alveoli
Alveoli are tiny air sacs with very thin walls and a rich blood supply, which is where oxygen enters the blood and carbon dioxide leaves it.
Source: Static General Science — competitive exam topic
- Q139EasyNutrition and Vitamins
Which of the following vitamins is water soluble?
- aVitamin A
- bVitamin D
- cVitamin E
- dVitamin C
Show the answer
Answer: d — Vitamin C
Vitamins C and those of the B group dissolve in water and are not stored, so they must be eaten regularly. A, D, E and K are fat soluble.
Source: Static General Science — competitive exam topic
- Q140MediumNutrition and Vitamins
A shortage of vitamin B1 in the diet causes which disease?
- aScurvy
- bRickets
- cBeriberi
- dGoitre
Show the answer
Answer: c — Beriberi
Beriberi follows a lack of thiamine and affects the nerves and heart. It was common where polished rice was the staple food.
Source: Static General Science — competitive exam topic
- Q141EasyNutrition and Vitamins
Which class of food is the body's main source of energy?
- aProteins
- bMinerals
- cVitamins
- dCarbohydrates
Show the answer
Answer: d — Carbohydrates
Carbohydrates are broken down to glucose and supply most day-to-day energy. Proteins mainly build and repair tissue.
Source: Static General Science — competitive exam topic
- Q142EasyDiseases and Pathogens
AIDS is caused by which virus?
- aHPV
- bHIV
- cHBV
- dEBV
Show the answer
Answer: b — HIV
The human immunodeficiency virus attacks the immune system, leaving the body open to infections it would normally resist.
Source: Static General Science — competitive exam topic
- Q143MediumDiseases and Pathogens
Wuchereria bancrofti, the commonest cause of filariasis in India, is carried by which mosquito?
- aAedes
- bAnopheles
- cMansonia
- dCulex
Show the answer
Answer: d — Culex
Culex carries Wuchereria bancrofti. Anopheles carries malaria and Aedes dengue, so each genus is associated with its own disease.
Source: Static General Science — competitive exam topic
- Q144MediumDiseases and Pathogens
The BCG vaccine gives protection against which disease?
- aPolio
- bMeasles
- cTetanus
- dTuberculosis
Show the answer
Answer: d — Tuberculosis
BCG is given in infancy to protect against tuberculosis, particularly its severe forms in young children.
Source: Static General Science — competitive exam topic
- Q145EasyPlant Biology
Which part of a flower develops into the fruit?
- aStigma
- bPetal
- cOvary
- dSepal
Show the answer
Answer: c — Ovary
After fertilisation the ovary grows into the fruit and the ovules inside it become the seeds. Petals and sepals usually fall away.
Source: Static General Science — competitive exam topic
- Q146MediumPlant Biology
Root nodules of leguminous plants help to fix which element from the air?
- aOxygen
- bNitrogen
- cCarbon
- dHydrogen
Show the answer
Answer: b — Nitrogen
Bacteria living in the nodules convert atmospheric nitrogen into compounds the plant can use, which is why pulses enrich the soil.
Source: Static General Science — competitive exam topic
- Q147HardPlant Biology
Which plant hormone is chiefly responsible for cell elongation and growth towards light?
- aAuxin
- bAbscisic acid
- cEthylene
- dCytokinin
Show the answer
Answer: a — Auxin
Auxin gathers on the shaded side of a shoot and makes those cells lengthen, which bends the plant towards the light. Ethylene ripens fruit instead.
Source: Static General Science — competitive exam topic
- Q148EasyScience and Technology
Who was the first woman of Indian origin to travel into space?
- aThomas Edison
- bGuglielmo Marconi
- cAlexander Graham Bell
- dMichael Faraday
Show the answer
Answer: c — Alexander Graham Bell
Kalpana Chawla was the first woman of Indian origin to travel into space. She flew on Space Shuttle Columbia in 1997 and again in 2003.
Source: Static General Science — competitive exam topic
- Q149EasyScience and Technology
Which instrument is used to record the tremors of an earthquake?
- aOdometer
- bSeismograph
- cAltimeter
- dManometer
Show the answer
Answer: b — Seismograph
A seismograph traces ground movement on a moving chart. An odometer counts distance travelled and an altimeter measures height above sea level.
Source: Static General Science — competitive exam topic
- Q150EasyScience and Technology
In space research, PSLV stands for which of the following?
- aPrecision Satellite Launch Vehicle
- bPolar Space Launch Vehicle
- cPolar Satellite Launch Vehicle
- dPayload Satellite Launch Vehicle
Show the answer
Answer: c — Polar Satellite Launch Vehicle
The PSLV places satellites into polar orbits and has been ISRO's most frequently used launcher. The GSLV carries heavier payloads to geostationary orbit.
Source: Static General Science — competitive exam topic
- Q151EasyUnits and Measurement
Frequency is measured in which SI unit?
- aHertz
- bDecibel
- cMetre
- dSecond
Show the answer
Answer: a — Hertz
One hertz means one cycle per second. The decibel is used for loudness instead and is not an SI base or derived unit of frequency.
Source: Static General Science — competitive exam topic
- Q152MediumUnits and Measurement
What is the normal term of office of the President of India?
- aMetre
- bKilogram
- cSecond
- dNewton
Show the answer
Answer: d — Newton
The President of India holds office for a term of five years from the date on which they enter office, subject to the constitutional provisions governing succession and re-election.
Source: Static General Science — competitive exam topic
- Q153MediumMotion and Force
Which law of motion gives the relation between force, mass and acceleration?
- aNewton's first law
- bNewton's third law
- cNewton's law of gravitation
- dNewton's second law
Show the answer
Answer: d — Newton's second law
The second law states that force equals mass times acceleration, which is what makes force measurable rather than merely described.
Source: Static General Science — competitive exam topic
- Q154EasyMotion and Force
A ball thrown straight upwards has zero velocity at which point?
- aAt its highest point
- bJust after it is thrown
- cHalfway up
- dJust before it lands
Show the answer
Answer: a — At its highest point
The ball slows as it rises and stops momentarily at the top before falling back. Its acceleration stays equal to gravity throughout, even at that instant.
Source: Static General Science — competitive exam topic
- Q155MediumMotion and Force
In physics, work is said to be done only when which condition is met?
- aA force is applied to a body
- bA body is held steady against gravity
- cA force produces displacement
- dA body moves at constant speed
Show the answer
Answer: c — A force produces displacement
Work equals force times displacement in the direction of the force. Holding a heavy bag still is tiring but does no work in the physical sense.
Source: Static General Science — competitive exam topic
- Q156HardMotion and Force
A lever and a pulley are useful because they change which aspect of a task?
- aThe total work that must be done
- bThe effort needed to do the same work
- cThe energy created during the task
- dThe mass of the load being moved
Show the answer
Answer: b — The effort needed to do the same work
A simple machine trades distance for force, so less effort is needed over a longer movement. The work done is never reduced, and no machine creates energy.
Source: Static General Science — competitive exam topic
- Q157MediumLight and Optics
A rainbow is formed by which combination of effects in raindrops?
- aAbsorption and scattering
- bDiffraction and polarisation
- cDispersion and internal reflection
- dConduction and radiation
Show the answer
Answer: c — Dispersion and internal reflection
Each drop splits sunlight into colours and reflects them back from its inner surface, so the observer sees a coloured arc with the Sun behind them.
Source: Static General Science — competitive exam topic
- Q158EasyLight and Optics
Which type of mirror does a dentist use to see an enlarged image of a tooth?
- aConcave mirror
- bConvex mirror
- cPlane mirror
- dParabolic mirror
Show the answer
Answer: a — Concave mirror
A concave mirror gives an enlarged upright image when the object is close to it, which is what lets a dentist examine a tooth in detail.
Source: Static General Science — competitive exam topic
- Q159HardLight and Optics
The power of a lens is measured in which unit?
- aDioptre
- bWatt
- cLumen
- dCandela
Show the answer
Answer: a — Dioptre
Lens power is the reciprocal of focal length in metres and is measured in dioptres. The lumen and candela measure quantities of light instead.
Source: Static General Science — competitive exam topic
- Q160EasySound and Waves
The loudness of a sound depends chiefly on which property of the wave?
- aFrequency
- bWavelength
- cAmplitude
- dSpeed
Show the answer
Answer: c — Amplitude
A larger amplitude carries more energy and sounds louder. Frequency decides the pitch, which is a different quality altogether.
Source: Static General Science — competitive exam topic
- Q161EasySound and Waves
Sound travels most slowly through which of the following?
- aWater
- bAir
- cIron
- dGlass
Show the answer
Answer: b — Air
Particles in a gas are far apart, so a vibration passes between them slowly. Sound moves faster in liquids and fastest of all in solids.
Source: Static General Science — competitive exam topic
- Q162EasyHeat and Thermodynamics
Heat passing along a metal rod held in a flame travels by which process?
- aConduction
- bConvection
- cRadiation
- dEvaporation
Show the answer
Answer: a — Conduction
In conduction the particles pass energy along without moving from their places, which is why metals feel hot at the far end so quickly.
Source: Static General Science — competitive exam topic
- Q163MediumHeat and Thermodynamics
In a vacuum flask, what does the vacuum between the two walls prevent?
- aRadiation only
- bEvaporation only
- cAll heat loss entirely
- dConduction and convection
Show the answer
Answer: d — Conduction and convection
A vacuum has no particles, so neither conduction nor convection can cross it. Radiation still can, which is why the walls are also silvered.
Source: Static General Science — competitive exam topic
- Q164MediumElectricity and Magnetism
An electric bell works on which effect of electric current?
- aHeating effect
- bChemical effect
- cPhotoelectric effect
- dMagnetic effect
Show the answer
Answer: d — Magnetic effect
Current through a coil makes an electromagnet that pulls the striker onto the gong, breaking the circuit and repeating the cycle rapidly.
Source: Static General Science — competitive exam topic
- Q165MediumElectricity and Magnetism
Metal-bodied electrical appliances are earthed mainly for which reason?
- aTo reduce the power the appliance consumes
- bTo carry leaked current safely to the ground
- cTo protect the appliance from voltage surges
- dTo complete the circuit for normal running
Show the answer
Answer: b — To carry leaked current safely to the ground
If a live wire touches the metal body, the earth wire offers a low resistance path away and the user is not shocked. The appliance runs perfectly well without it, which is what makes the fault dangerous.
Source: Static General Science — competitive exam topic
- Q166MediumAtomic Structure
The mass number of an atom is the total number of which particles?
- aProtons and electrons
- bNeutrons and electrons
- cProtons only
- dProtons and neutrons
Show the answer
Answer: d — Protons and neutrons
Protons and neutrons carry almost all the mass and together give the mass number. Electrons are far too light to affect it appreciably.
Source: Static General Science — competitive exam topic
- Q167HardAtomic Structure
Rutherford's famous scattering experiment used a beam of which particles?
- aBeta particles
- bNeutrons
- cAlpha particles
- dX-rays
Show the answer
Answer: c — Alpha particles
Alpha particles fired at gold foil mostly passed through, but a few bounced back, which showed the atom has a small dense positive nucleus.
Source: Static General Science — competitive exam topic
- Q168EasyPeriodic Table and Elements
The modern periodic table arranges elements in order of which property?
- aIncreasing atomic mass
- bDecreasing density
- cIncreasing melting point
- dIncreasing atomic number
Show the answer
Answer: d — Increasing atomic number
Moseley showed that properties follow the atomic number. Mendeleev had used atomic mass, which left several pairs of elements out of order.
Source: Static General Science — competitive exam topic
- Q169MediumPeriodic Table and Elements
Which element does the chemical symbol Fe represent?
- aIron
- bFluorine
- cFrancium
- dFermium
Show the answer
Answer: a — Iron
Iron takes Fe from the Latin ferrum. Fluorine is F, so the two are easy to confuse when only the first letter is remembered.
Source: Static General Science — competitive exam topic
- Q170EasyPeriodic Table and Elements
Which gas is used in airships because it is lighter than air and does not burn?
- aHydrogen
- bOxygen
- cHelium
- dNitrogen
Show the answer
Answer: c — Helium
Helium gives slightly less lift than hydrogen but will not catch fire, which is why airships use it after the hydrogen airship disasters.
Source: Static General Science — competitive exam topic
- Q171EasyAcids Bases and Salts
Baking soda makes cakes rise because on heating it releases which gas?
- aOxygen
- bCarbon dioxide
- cHydrogen
- dNitrogen
Show the answer
Answer: b — Carbon dioxide
Sodium bicarbonate breaks down on heating and gives off carbon dioxide, and the trapped bubbles make the batter light and porous.
Source: Static General Science — competitive exam topic
- Q172MediumAcids Bases and Salts
The pH value of lemon juice is likely to be:
- aExactly 7
- bLess than 7
- cBetween 8 and 10
- dGreater than 12
Show the answer
Answer: b — Less than 7
Lemon juice contains citric acid, so its pH falls below 7. Values above 7 belong to bases such as soap solution.
Source: Static General Science — competitive exam topic
- Q173EasyMetals and Non-metals
Which metal is widely used in aircraft bodies because of its low density?
- aIron
- bLead
- cCopper
- dAluminium
Show the answer
Answer: d — Aluminium
Aluminium alloys are strong for their weight and resist corrosion, which is exactly what an airframe needs.
Source: Static General Science — competitive exam topic
- Q174MediumMetals and Non-metals
Which metal is stored under kerosene because it reacts violently with air and water?
- aSodium
- bCopper
- cZinc
- dSilver
Show the answer
Answer: a — Sodium
Sodium catches fire on contact with water and tarnishes instantly in air, so it is kept under kerosene, which excludes both.
Source: Static General Science — competitive exam topic
- Q175MediumCarbon and Organic Chemistry
Diamond and graphite differ in properties although both are made of carbon. They are called:
- aAllotropes
- bIsotopes
- cIsomers
- dIsobars
Show the answer
Answer: a — Allotropes
Allotropes are different structural forms of the same element. Isotopes differ in neutron number and isomers are compounds with the same formula but different arrangements.
Source: Static General Science — competitive exam topic
- Q176MediumCarbon and Organic Chemistry
Biogas produced from cow dung consists mainly of which gas?
- aEthane
- bMethane
- cButane
- dCarbon monoxide
Show the answer
Answer: b — Methane
Bacteria break down organic waste without air and produce mostly methane, which burns cleanly and makes biogas a useful rural fuel.
Source: Static General Science — competitive exam topic
- Q177EasyEveryday Chemistry
Which acid gives curd and sour milk their sour taste?
- aCitric acid
- bAcetic acid
- cLactic acid
- dFormic acid
Show the answer
Answer: c — Lactic acid
Bacteria turn the lactose of milk into lactic acid, which sours it and sets the curd. Formic acid is found in ant stings instead.
Source: Static General Science — competitive exam topic
- Q178MediumEveryday Chemistry
Which of the following is NOT a greenhouse gas?
- aCarbon dioxide
- bNitrogen
- cMethane
- dNitrous oxide
Show the answer
Answer: b — Nitrogen
Nitrogen makes up most of the air but does not absorb the heat the Earth radiates. Carbon dioxide, methane and nitrous oxide all do, which is what traps warmth.
Source: Static General Science — competitive exam topic
- Q179EasyEveryday Chemistry
Dry ice is the solid form of which substance?
- aCarbon dioxide
- bWater
- cAmmonia
- dNitrogen
Show the answer
Answer: a — Carbon dioxide
Solid carbon dioxide sublimes straight into gas without melting, so it cools without leaving any liquid behind.
Source: Static General Science — competitive exam topic
- Q180HardCell Biology
The cell theory was proposed by which pair of scientists?
- aWatson and Crick
- bDarwin and Wallace
- cSchleiden and Schwann
- dMendel and Morgan
Show the answer
Answer: c — Schleiden and Schwann
Schleiden studied plants and Schwann animals, and together they concluded that all living things are made of cells. Watson and Crick worked on DNA.
Source: Static General Science — competitive exam topic
- Q181EasyCell Biology
Fiscal deficit is broadly calculated as:
- aProtoplasm
- bNucleoplasm
- cPlasma
- dCytoplasm
Show the answer
Answer: d — Cytoplasm
Fiscal deficit is the excess of total government expenditure over total receipts excluding borrowings. It indicates the amount the government needs to finance through borrowing and other financing sources.
Source: Static General Science — competitive exam topic
- Q182MediumHuman Body Systems
Bile, which helps in the digestion of fat, is produced by which organ?
- aGall bladder
- bStomach
- cSmall intestine
- dLiver
Show the answer
Answer: d — Liver
The liver makes bile and the gall bladder only stores it until food arrives. Bile breaks fat into small droplets so enzymes can act on it.
Source: Static General Science — competitive exam topic
- Q183EasyHuman Body Systems
How many teeth does a normal adult human have?
- a28
- b32
- c20
- d36
Show the answer
Answer: b — 32
An adult has 32 permanent teeth including the four wisdom teeth. A child has 20 milk teeth, which are gradually replaced.
Source: Static General Science — competitive exam topic
- Q184EasyHuman Body Systems
What does the IFSC code identify in India's electronic banking system?
- aArtery
- bVein
- cCapillary
- dLymph vessel
Show the answer
Answer: a — Artery
The Indian Financial System Code (IFSC) is an 11-character alphanumeric code that identifies a particular bank branch for electronic payment systems such as NEFT and RTGS.
Source: Static General Science — competitive exam topic
- Q185MediumHuman Body Systems
Red blood cells are produced mainly in which part of the body?
- aLiver
- bBone marrow
- cSpleen
- dKidney
Show the answer
Answer: b — Bone marrow
Red marrow inside the bones makes red blood cells throughout life. The spleen stores blood and removes worn-out cells rather than making them.
Source: Static General Science — competitive exam topic
- Q186HardHuman Body Systems
Which instrument is used to measure blood pressure?
- aSphygmomanometer
- bStethoscope
- cThermometer
- dSpirometer
Show the answer
Answer: a — Sphygmomanometer
A sphygmomanometer measures blood pressure with an inflatable cuff. A stethoscope only listens, and a spirometer measures lung capacity.
Source: Static General Science — competitive exam topic
- Q187EasyNutrition and Vitamins
Which mineral is most needed for the building of strong bones and teeth?
- aIron
- bSodium
- cCalcium
- dPotassium
Show the answer
Answer: c — Calcium
Calcium hardens bone and enamel, and vitamin D is needed for the body to absorb it. Iron is required for blood rather than bone.
Source: Static General Science — competitive exam topic
- Q188EasyNutrition and Vitamins
Eating citrus fruits such as oranges and lemons chiefly prevents which disease?
- aRickets
- bScurvy
- cGoitre
- dBeriberi
Show the answer
Answer: b — Scurvy
Citrus fruits are rich in vitamin C, and scurvy is what follows a lack of it. Sailors on long voyages once suffered from it badly.
Source: Static General Science — competitive exam topic
- Q189MediumNutrition and Vitamins
Which of these foods is the best source of roughage in the diet?
- aPolished white rice
- bFruit juice with the pulp removed
- cRefined wheat flour
- dWhole grains and green vegetables
Show the answer
Answer: d — Whole grains and green vegetables
Roughage is dietary fibre, and refining strips it out. Whole grains and vegetables keep it, which is why they help food move through the intestine.
Source: Static General Science — competitive exam topic
- Q190EasyDiseases and Pathogens
Diabetes mellitus results from a shortage or poor use of which hormone?
- aAdrenaline
- bThyroxine
- cInsulin
- dOestrogen
Show the answer
Answer: c — Insulin
Insulin lets cells take glucose from the blood, so too little of it leaves blood sugar high. Thyroxine controls the rate of metabolism instead.
Source: Static General Science — competitive exam topic
- Q191MediumDiseases and Pathogens
Plague is transmitted to humans chiefly by which creature?
- aHousefly
- bSandfly
- cTsetse fly
- dRat flea
Show the answer
Answer: d — Rat flea
The bacterium is carried by fleas living on rats and passes to people when the flea bites. The sandfly spreads kala-azar and the tsetse fly sleeping sickness.
Source: Static General Science — competitive exam topic
- Q192MediumDiseases and Pathogens
How many Nobel Prize categories are commonly counted today, including the prize in Economic Sciences?
- aThe inner ear
- bThe lens of the eye
- cThe kidney
- dThe heart valve
Show the answer
Answer: b — The lens of the eye
Six categories are commonly counted today: Physics, Chemistry, Physiology or Medicine, Literature, Peace, and Economic Sciences. The Economic Sciences prize was established by Sweden's central bank in 1968 in memory of Alfred Nobel and is not one of the original prizes specified in Nobel's will.
Source: Static General Science — competitive exam topic
- Q193EasyDiseases and Pathogens
Antibiotics are effective against which kind of organism?
- aViruses
- bAll microbes equally
- cOnly fungi
- dBacteria
Show the answer
Answer: d — Bacteria
Antibiotics attack structures that bacteria have and human cells do not. Viruses lack those structures, which is why antibiotics do nothing for a common cold.
Source: Static General Science — competitive exam topic
- Q194MediumPlant Biology
Plants release energy from stored food by which process?
- aPhotosynthesis
- bTranspiration
- cPollination
- dRespiration
Show the answer
Answer: d — Respiration
Plants respire day and night, taking in oxygen and releasing carbon dioxide. Photosynthesis works the other way and needs light.
Source: Static General Science — competitive exam topic
- Q195MediumPlant Biology
The male reproductive part of a flower is called the:
- aPistil
- bSepal
- cStamen
- dReceptacle
Show the answer
Answer: c — Stamen
The stamen carries the anther, which produces pollen. The pistil is the female part and holds the stigma, style and ovary.
Source: Static General Science — competitive exam topic
- Q196EasyPlant Biology
In pollination, pollen is transferred from the anther to which part of the flower?
- aOvary
- bStigma
- cSepal
- dReceptacle
Show the answer
Answer: b — Stigma
Pollen lands on the stigma and grows a tube down the style to reach the ovary, where fertilisation takes place.
Source: Static General Science — competitive exam topic
- Q197EasyScience and Technology
Who discovered penicillin?
- aAlexander Fleming
- bLouis Pasteur
- cEdward Jenner
- dRobert Koch
Show the answer
Answer: a — Alexander Fleming
Fleming noticed in 1928 that a mould killed bacteria on a culture plate. Jenner developed vaccination and Koch identified the tuberculosis bacterium.
Source: Static General Science — competitive exam topic
- Q198EasyScience and Technology
Who was the first person to walk on the Moon?
- aYuri Gagarin
- bBuzz Aldrin
- cNeil Armstrong
- dMichael Collins
Show the answer
Answer: c — Neil Armstrong
Neil Armstrong became the first person to walk on the Moon during NASA's Apollo 11 mission in July 1969. Buzz Aldrin followed shortly afterward.
Source: Static General Science — competitive exam topic
- Q199MediumScience and Technology
An electric cell supplies current by converting which form of energy?
- aMechanical energy
- bChemical energy
- cSolar energy
- dNuclear energy
Show the answer
Answer: b — Chemical energy
Reactions between the electrodes and the electrolyte release energy as an electric current. A dynamo instead converts mechanical energy.
Source: Static General Science — competitive exam topic
- Q200EasyScience and Technology
Which Indian space mission was sent to orbit Mars?
- aChandrayaan
- bAryabhata
- cMangalyaan
- dRohini
Show the answer
Answer: c — Mangalyaan
India's Mars Orbiter Mission, popularly known as Mangalyaan, entered Mars orbit in September 2014. It was India's first interplanetary mission.
Source: Static General Science — competitive exam topic
Answers are compiled by hand and may contain mistakes. Where a question came from a real paper, the official key governs.