st Search

Q:

During thunderstorm you are travelling in a car. To protect yourself from the lightning you will have to

A) remain in the car	B) get out of the car and lie flat in the ground
C) abandon the car and take shelter under a nearby tree	D) touch the nearest electric pole

Answer & Explanation Answer: A) remain in the car

Explanation:

The Whole car - the body and inside - can be considered to be a hallow conductor. During the thunderstorm the body - i.e, the outside- gets a charge but there will be no charge inside. so the inside is safe.

Report Error

View Answer Report Error Discuss

Filed Under: Physics

Q:

When white light passes through a glass prism we get a spectrum on the other side of the prism. In the emergent beam the ray which is deviated least is

A) the violet ray	B) the red ray
C) the green ray	D) the blue ray

Answer & Explanation Answer: B) the red ray

Explanation:

Red is deviated the least and violet the most

Report Error

View Answer Report Error Discuss

Filed Under: Physics

Q:

A series of fast moving still pictures can be made to appear as a moving picture because the eye

A) can focus very rapidly as pictures change	B) is quicker than the brain
C) can see 2 images separated only if the interval betwen seeing them is more than one-tenth of a second	D) can shut out some of the light

Answer & Explanation Answer: C) can see 2 images separated only if the interval betwen seeing them is more than one-tenth of a second

Explanation:

The eye can see images separately only if they are exhibited at an interval of more than 1/10 of a second. In the case of a movie, the still pictures come one after the other at less than this minimum interval. So we do not see them separately but only as a continuous moving picture.

Report Error

View Answer Report Error Discuss

Filed Under: Physics

Q:

Hot water is poured simultaneously in four metallic tumblers painted outside with different paints. After some time the water will be found to have cooled most in the tumbler painted.

A) rough white	B) rough black
C) shining white	D) shining black

Answer & Explanation Answer: B) rough black

Explanation:

Black surfaces are good emitters of heat. If the black surface is rough too, the emitting will be better. Shinning surfaces reflect black radiation . So if the black surface is also shining the effectiveness of emitting heat is lessened.

Report Error

View Answer Report Error Discuss

Filed Under: Physics

Q:

Radio waves sent out by a radio stations are reflected by

A) troposphere	B) stratosphere
C) mesosphere	D) ionosphere

Answer & Explanation Answer: D) ionosphere

Explanation:

This is a layer of atmosphere about 60 to 70 km above the earth and extends to about 400km. It contains ionised particles which can reflect radio waves making radio communication round the world possible.

Report Error

View Answer Report Error Discuss

Filed Under: Physics

Q:

A stone floor feels cold to the bare feet but a carpet on the same floor feels warm. This is because

A) the floor and carpet are at different temperatures	B) the stone conveys the heat away from the feet more rapidly than the carpet
C) the carpet is a better conductor of heat than the stone	D) the human body maintains a constant temperature

Answer & Explanation Answer: B) the stone conveys the heat away from the feet more rapidly than the carpet

Explanation:

Both the floor and the carpet have the same temperature as both are exposed to the same atmosphere. But the former conducts away the heat from the feet better than the carpet as the latter is a non-conductor. So the feet losing more heat, the floor appears cooler to the feet.

Report Error

View Answer Report Error Discuss

Filed Under: Physics

Q:

A man stands on the pan of a balance holding a fish in his right hand and bucket of water in his left hand. If he transfers the fish into the bucket, the total weight on the pan

A) increases	B) decreases
C) remains the same	D) first increases and then decreases

Answer & Explanation Answer: C) remains the same

Explanation:

Before transferring the fish, the position is the man with the fish and the bucket of water. After transferring the position is : the man without the fish, but the fish inside the water in the bucket. Thus to know whether there is any change in weight, it is enough to consider whether there is any change in weight when the fish in air is transferred into the water. The answer is there is no change as when in water though it loses weight due to upthrust of water on it, the level of water increases and exerts an equal force at the bottom

Report Error

View Answer Report Error Discuss

Filed Under: Physics

Q:

The inability of a body to change its state of rest or uniform motion along a straight line is called its

A) momentum	B) velocity
C) acceleration	D) inertia

Searching for "st"

Quick Links