Previous Year Questions General Science for CDS & CAPF: 3rd October

Previous year questions must be prepared when it comes to the preparation of CDS & CAPF examinations. Defenceadda is providing you with the previous year questions of General Science Section.

Q1.  The blackboard seems black because it 
(a) Reflects every colour 
(b) Does not reflect any colour 
(c) Absorbs black colour 
(d) Reflects black colour

Q2. Mr X was advised by an architect to make outer walls of his house with hollow bricks. The correct reason is that such walls  
(a) Make the building stronger 
(b) Help keeping inside cooler in summer and warmer in winter 
(c) Prevent seepage of moisture from outside 
(d) Protect the building from lightning

Q3. If a ship moves from freshwater into seawater, it will 
(a) Sink completely 
(b) Sink a little bit 
(c) Rise a little higher 
(d) Remain unaffected

Q4. Viewfinders, used in automobiles to locate the position of the vehicles behind, are made of  
(a) Plane mirror 
(b) Concave mirror 
(c) Convex mirror 
(d) Parabolic mirror

Q5. The cat can survive fall from a height much more than human or any other animal. It is because the cat  
(a) Can immediately adjust itself to land on all four paws and bend the legs to absorb the impact of falling 
(b) Has elastic bones 
(c) Has thick and elastic skin 
(d) Also gets injury equally with other animals, but has tremendous endurance, resistance and speedy recovery

Q6. Fire fly gives us cold light by virtue of the phenomenon of 
(a) Fluorescence 
(b) Phosphorescence 
(c) Chemiluminescence 
(d) Effervescence

Q7. Transformer is a kind of appliance that can  
1. Increase power 
2. Increase voltage 
3. Decrease voltage 
4. Measure current and voltage 
Select the correct answer using the codes given below 
(a) Only 4 
(b) 1 and 4 
(c) 2 and 3 
(d) 2, 3 and 4

Q8. A body has a mass of 6 kg on the Earth; when measured on the Moon, its mass would be  
(a) Nearly 1 kg 
(b) Less than 1 kg 
(c) Less than 6 kg 
(d) 6 kg

Q9. When a ball drops onto the floor it bounces. Why does it bounce?  
(a) Newton’s third law implies that for every action (drop) there is a reaction (bounce) 
(b) The floor exerts a force on the ball during the impact 
(c) The floor is perfectly rigid 
(d) The floor heats up on impact

Q10. If the door of a running refrigerator in a closed room is kept open, what will be the net effect on the room? 
(a) It will cool the room 
(b) It will heat the room 
(c) It will make no difference on the average 
(d) It will make the temperature go up and down 

S1. Ans.(b)
Sol. Blackboard absorbs all the colours of light falling on it and does not reflect any colour due to which it appears black.

S2. Ans.(b)
Sol. The hollow bricks provide thermal insulations; the air in hollow bricks, does not allow outside heat or cold in the house to go out or come in the house. So, it keeps house cool in summer and warm in winter.

S3. Ans.(c)
Sol. When a body is immersed in a fluid, the fluid exerts an upward force on it, called buoyant force. 
And buoyant force ∝ density of fluid. 
As the density of sea water is higher than that of the fresh water.

S4. Ans.(c)
Sol. In automobiles, convex mirror is used as a rear view mirror because the image of the vehicle formed is small in size due to this the field of view is increased and the driver of automobile can see the traffic over larger area.

S5. Ans.(a)
Sol. As the cat falls from a height, it bends the legs to absorb the impact of falling and immediately adjust itself.

S6. Ans.(c)
Sol. Fire fly gives us cold light due to chemiluminescence i.e. light produced by chemical reaction.

S7. Ans.(c)
Sol. Transformer is an appliance that can increase or decrease voltage.

S8. Ans.(d)
Sol. Mass of an object does not change when an objects location changes. It is the weight of the body (w = mg) which changes with value of ‘g’ at that place.

S9. Ans.(b)
Sol. When a ball drops on to the floor then floor exerts a force for small time which is equal to change in momentum of the ball.

S10. Ans.(b)
Sol. It will heat the room because the heat removed from the inside is released into the room, counter acting any cooling, plus the energy that is used to operate the compressor eventually winds up being heat, therefore increasing the room temperature. 

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