CDS Questions

GP Magnetism

Which one of the following devices changes low voltage alternating current to high voltage alternating current and vice versa?

  1. Generator
  2. Motor
  3. Transformer
  4. Vibrator

GP Light

An optical illusion which occurs mainly in deserts during hot summer is based on the principle of

  1. Reflection
  2. Interference
  3. Dispersion
  4. Total internal reflection

GP Magnetism

At which place Earth’s magnetic field becomes horizontal?

  1. Magnetic meridian
  2. Magnetic equator
  3. Geographical pole
  4. Tropic of Cancer

GP Motion Force

The speed of a car travelling on a straight road is listed below at successive intervals of 1 s:
Time (s)        0 1 2 3 4
Speed (m/s)  0 2 4 6 8

Which of the following is/are correct?

The car travels

  1. with a uniform acceleration of 2 m/s2.
  2. 16 m in 4 s.
  3. with an average speed of 4 m/s.

Select the correct answer using the code given below:

  1. 1, 2 and 3
  2. 2 and 3 only
  3. 1 and 2 only
  4. 1 only

GP Sound Waves

The speed of a body that has Mach number more than 1 is

  1. supersonic
  2. subsonic
  3. 300 m/s
  4. about 10 m/s

GC Acids Bases Salts

Consider the following reaction:

CH4 + 2O2 → CO2 + 2H2O

Which of the following about the reaction given above is/are correct?

  1. Carbon is oxidized.
  2. Hydrogen is oxidized.
  3. Hydrogen is reduced.
  4. Carbon is reduced.

Select the correct answer using the code given below:

  1. 1 only
  2. 1 and 2 only
  3. 2 and 3 only
  4. 2 and 4 only

GC Acids Bases Salts

The desirable range of pH for drinking water is

  1. 6.5 to 8.5
  2. 5.0 to 6.5
  3. 6.5 to 7.0
  4. 7.0 to 8.5

GS Environment

Which one of the following is a cause of acid rains?

  1. Ozone
  2. Ammonia
  3. Sulphur dioxide
  4. Carbon monoxide

GP Sound Waves

Which one of the following waves does not belong to the category of the other three?

  1. X-rays
  2. Microwaves
  3. Radio waves
  4. Sound waves

GP Sound Waves

Bats detect obstacles in their path by receiving the reflected

  1. Infrasonic waves
  2. Ultrasonic waves
  3. Radio waves
  4. Microwaves

GP Light

A rainbow is produced due to which one of the following phenomena?

  1. Dispersion of light
  2. Interference of light
  3. Diffraction of light
  4. Scattering of light by atmospheric dust

GC Acids Bases Salts

Why is potassium permanganate used for purifying drinking water?

  1. It kills germs
  2. It dissolves the impurities
  3. It is a reducing agent
  4. It is an oxidizing agent

GC Metals Non-Metals

Which one among the following chemicals is used as washing soda?

  1. Calcium carbonate
  2. Calcium bicarbonate
  3. Sodium carbonate
  4. Sodium bicarbonate

GS Environment

Which one of the following gases is placed second in respect of abundance in the Earth's atmosphere?

  1. Oxygen
  2. Hydrogen
  3. Nitrogen
  4. Carbon dioxide

GC Acids Bases Salts GC Metals Non-Metals

Zinc is used to protect iron from corrosion because zinc is

  1. more electropositive than iron
  2. cheaper than iron
  3. a bluish white metal
  4. a good conductor of heat and electricity

GC Atomic Structure

How much CO2 is produced on heating of 1 kg of carbon?

  1. 11/3 kg 
  2. 3/11 kg
  3. 4/3 kg
  4. 3/4 kg

GP Sound Waves

Which one among the following waves carries the maximum energy per photon?

  1. X-rays
  2. Radio waves
  3. Light waves
  4. Microwaves

GP Magnetism

Step-up transformers are used for

  1. increasing electrical power
  2. decreasing electrical power
  3. decreasing voltage
  4. increasing voltage

GP Solids Fluids

If some object is weighed when submerged in water, what will happen to its weight compared to its weight in air?

  1. Increase
  2. Decrease
  3. Remain exactly the same
  4. Increase or decrease cannot be predicted

GP Light

Concave mirror is used in headlights of vehicles, because it

  1. focuses light from the bulb onto nearby vehicles
  2. sends parallel rays
  3. fits well into the shape of the headlight
  4. is cheaper than other mirrors

GS Water

Water boils at a lower temperature at high altitudes, because

  1. the air pressure is less
  2. outside temperature is less
  3. less latent heat is less
  4. None of the above

GB Living Organisms

Which one of the following microbes causes acidification and curdling of milk?

  1. Lactic Acid Bacillus
  2. Clostridium botulinum
  3. Vibrio cholerae
  4. Saccharomyces cerevisiae

GB Health

The term 'Probiotic' is applied to

  1. Organic food
  2. Antacid
  3. Antibiotic
  4. Live microbial food supplement

GC Metals Non-Metals

Which of the following statements about magnetite ore of iron is/are correct?

  1. It is known as black ore.
  2. It contains 60% to 70% of pure iron.
  3. It possesses magnetic properties.

Select the correct answer using the codes given below:

  1. 1 only
  2. 2 and 3 only
  3. 1 and 3 only
  4. 1, 2 and 3

GC Atomic Structure

The compound C6H12O4 contains

  1. 22 atoms per mole
  2. twice the mass percent of H as compared to the mass percent of C
  3. six times the mass percent of C as compared to the mass percent of H
  4. thrice the mass percent of H as compared to the mass percent of 0

GS Water

When pure water boils vigorously, the bubbles that rise to the surface are composed primarily of

  1. air
  2. hydrogen
  3. hydrogen and oxygen
  4. water vapour

GC Atomic Structure

The ionization energy of hydrogen atom in the ground state is

  1. 13.6 MeV
  2. 13.6 eV
  3. 13.6 Joule
  4. Zero

GP Sound Waves

Which one of the following waves is used for detecting forgery in currency notes?

  1. Ultraviolet waves
  2. Infrared waves
  3. Radio waves
  4. Microwaves

GP Light

The mirrors used as rear-view mirrors in vehicles are

  1. concave
  2. convex
  3. cylindrical
  4. plane

GP Light

How long does light take to reach the Earth from the Sun?

  1. About 4 minutes
  2. About 8 minutes
  3. About 24 minutes
  4. About 24 hours

GC Atomic Structure

Electron emission from a metallic surface by application of light is known as

  1. Thermionic emission
  2. Photoelectric emission
  3. High field emission
  4. Autoelectronic emission

GP Motion Force

In a vacuum, a five-rupee coin, a feather of a sparrow bird and a mango are dropped simultaneously from the same height. The time taken by them to reach the bottom is t1, t2 and t3 respectively. In this situation, we will observe that

  1. t1 > t2 > t3
  2. t1 > t3 > t2
  3. t3 > t1 > t2
  4. t1 = t2 = t3

GP Work Energy

The force acting on a particle of mass m moving along the x-axis is given by F(x) = Ax2 - Bx. Which one of the following is the potential energy of the particle?

  1. 2Ax - B
  2. -x2/6 (2Ax - 3B)
  3. Ax3 - Bx2
  4. Zero

GP Motion Force

An object moves in a circular path with a constant speed. Which one of the following statements is correct?

  1. The centripetal acceleration of the object is smaller for a gentle curve (i.e., curve of larger radius) than that for a sharp curve (i.e., curve of smaller radius).
  2. The centripetal acceleration is greater for a gentle curve than that for a sharp curve.
  3. The centripetal acceleration is the same for both, the gentle and sharp curves.
  4. The centripetal acceleration causes the object to slow down.

GB Reproduction Heredity

Golden rice is a genetically-modified crop plant where the incorporated gene is meant for biosynthesis of

  1. Omega-3 fatty acids
  2. Vitamin A
  3. Vitamin B
  4. Vitamin C

GB Living Organisms GB Health

Which one of the following is the scientific name of the causal organism of elephantiasis?

  1. Ascaris lumbricoides
  2. Culex pipiens
  3. Wuchereria bancrofti
  4. Fasciola hepatica

GC Metals Non-Metals

Which one of the following elements is used as a timekeeper in atomic clocks?

  1. Potassium
  2. Caesium
  3. Calcium
  4. Magnesium

GC Metals Non-Metals

Which one of the following elements is involved in the control of water content of the blood?

  1. Potassium
  2. Lithium
  3. Rubidium
  4. Caesium

GC Metals Non-Metals

Which one of the following gases dissolves in water to give acidic solution?

  1. Carbon dioxide
  2. Oxygen
  3. Nitrogen
  4. Hydrogen

GC Metals Non-Metals

Which one of the following elements is essential for the formation of chlorophyll in green plants?

  1. Calcium
  2. Iron
  3. Magnesium
  4. Potassium

GC Metals Non-Metals

Why is argon gas used along with tungsten wire in an electric bulb?

  1. To increase the life of the bulb
  2. To reduce the consumption of electricity
  3. To make the emitted light colored
  4. To reduce the cost of the bulb

GP Heat

Which one of the following is the correct relation between the Kelvin temperature (T) and the Celsius temperature (tc)?

  1. These are two independent temperature scales
  2. T = tc
  3. T = tc - 273.15
  4. T = tc + 273.15

GP Sound Waves

Sound waves cannot travel through a

  1. copper wire placed in air
  2. silver slab placed in air
  3. glass prism placed in water
  4. wooden hollow pipe placed in vacuum


There are five hobby clubs in a college viz., photography, yachting, chess, electronics and gardening. The gardening group meets every second day, the electronics group meets every third day, the chess group meets every fourth day, the yachting group meets every fifth day and the photography group meets every sixth day. How many times do all the five groups meet on the same day within 180 days?

  1. 5
  2. 3
  3. 18
  4. 10


Three persons start walking together and their steps measure 40 cm, 42 cm and 45 cm respectively. What is the minimum distance each should walk so that each can cover the same distance in complete steps?

  1. 75 m 60 cm
  2. 50 m 40 cm
  3. 25 m 20 cm
  4. 75 m 60 cm


In a fire range, four shooters are firing at their respective targets. The first, the second, the third and the fourth shooter hit the target once in every 5, 6, 7 and 8 seconds respectively. If all of them hit the target at 9:00 am, when will they hit their target together again.

  1. 9:04 am
  2. 9:08 am
  3. 9:10 am
  4. 9:14 am


What is the number of integral solutions of the equations HCF(a,b) = 5 and a + b = 65?

  1. Exactly one
  2. Infinitely many
  3. Less than 65
  4. None


If for integer a, b and c if HCF(a,b) = 1 and HCF(a,c) = 1, then which one of the following is correct?

  1. HCF(a,bc) = a
  2. HCF(a,bc) = b
  3. HCF(a,bc) = 1
  4. None


What is the HCF of 8(x5 - x3 + x) and 28(x6 + 1)?

  1. (x4 + 1 - x2)
  2. 4(x4 + 1 - x2)
  3. 2(x4 + 1 - x2)
  4. None


The product of two numbers is 6912 and their GCD is 24. What is their LCM

  1. 296
  2. 288
  3. 286
  4. 280