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Q:

When two similar sources vibrate with slightly different frequencies , a regular rise and fall occurs in the loudness of tone. This phenomenon is known as 

A) doppler effect B) beats
C) resonance D) echo
 
Answer & Explanation Answer: B) beats

Explanation:

Beats means the periodic increase and decrease in loudness heard when two notes of nearly the same frequency are sounded simultaneously.

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Filed Under: Physics

Q:

A car parked in the sun with its windows closed gets terribly hot inside. This is due to 

A) the heat emitted by the engine B) the greenhouse effect
C) the good conducting power of the metal body D) the double layered wind shield
 
Answer & Explanation Answer: B) the greenhouse effect

Explanation:

The green house effect. The waves of smaller wavelength from the sun enter inside the car through the glass windows and are absorbed. The waves of larger wavelength emitted from inside cannot get out through the glass, but remain inside and make it terribly hot.

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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.

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Q:

A balloon filled with hydrogen will

A) continue going upwards uninterrupted B) reach a particular height and remain floating
C) burst after reaching some height D) reach a particular height and start coming down
 
Answer & Explanation Answer: B) reach a particular height and remain floating

Explanation:

It will stop at a height where the weight of the balloon with contents is equal to the weight of air displaced by it, i.e , when the upthrust is equal to the downthrust. The question of bursting will depend on how much difference of pressure inside and outside , the material of the balloon can withstand. It is assumed the balloon is filled with a lighter than air gas like hydrogen or helium.

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Q:

A bucket of water is hung from a spring balance. A piece of iron is suspended in the water without touching the sides or touching the bottom of the bucket. The reading of the spring balance

A) will increase B) will decrease
C) does not change D) varies with the increase of depth of the immersion of the iron piece
 
Answer & Explanation Answer: A) will increase

Explanation:

When the piece of iron is lowered into the water, the water level in the bucket increases. And so the pressure at the bottom of bucket also increases. Thus the total thrust at the botto also increases. Therefore the spring balance reading increases.

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Q:

A hunter on the ground wishes to shoot a  bird on a tree at a distance with his rifle. He has to point the rifle

A) at the lower alevation than the bird B) at a higher alevation than the bird
C) In the same direction as the bird D) vertically upwards
 
Answer & Explanation Answer: B) at a higher alevation than the bird

Explanation:

The trajectory of the bullet is a parabola

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Filed Under: Physics

Q:

What do you call elements with Atomic Number between 57 and 71?

Answer

'Rare earth'(They are all metals)

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Subject: General Science

Q:

Which pop musician had his first major hit with a song titled "Heart break Hotel"?

Answer

Elvis Presley

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Subject: General Awareness