Physics Questions

Q:

The attenuation in optical fibre is mainly due to

A) Scattering B) Absorption
C) Both (a) and (b) D) Neither absorption nor scattering
 
Answer & Explanation Answer: A) Scattering

Explanation:

The reason for transmitting data over optical fibers, is because the speed of data transmission through optical wires are equal to the speed of light. The intense speed of data transfer speed, has lead to the use of optical fibers. The optical fiber uses the technology of transferring light beams, from one end to the other end of optical cables. The attenuation in optical fiber is due to Scattering. The reason why scattering is caused, due to the folding, in the wire.

 

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Q:

Air expands when it _______________.

A) is cooled B) is heated
C) is under pressure D) becomes more humid
 
Answer & Explanation Answer: B) is heated

Explanation:
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Q:

Which one of the following takes place during a nuclear fusion?

A) a heavy nucleus bombarded by neutrons breaks up B) a heavy nucleus breaks up spontaneously
C) two light nuclei combine to form a heavy nucleus D) a light nucleus breaks up spontaneously
 
Answer & Explanation Answer: C) two light nuclei combine to form a heavy nucleus

Explanation:
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Q:

Work done by a passenger standing on a platform holding a suitcase weighing 10kg is

A) 980 J B) 98 J
C) 0 J D) 100 J
 
Answer & Explanation Answer: C) 0 J

Explanation:
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Q:

What is the fundamental unit of amount of a substance?

A) Mole B) Candela
C) Kelvin D) Meter
 
Answer & Explanation Answer: A) Mole

Explanation:
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Q:

_______________ states that the ratio of the potential difference across a conductor to the current flowing through it, is a constant, provided that its physical conditions, such as temperature, remain constant.

A) Lenz's Law B) Hooke's Law
C) Ohm's Law D) The coulomb's law
 
Answer & Explanation Answer: C) Ohm's Law

Explanation:
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Q:

Pressure cooker cooks rice faster because

A) it always lets the steam escape B) high pressure raises the boiling point of water
C) high pressure crushes the hard covering of rice grains D) it does not let the heat energy escape easily
 
Answer & Explanation Answer: B) high pressure raises the boiling point of water

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Q:

The theory behind stars twinkling is that

A) The refractive index of the different layers of earth's atmosphere changes continuously, consequently the position of the star's image changes with time B) The intensity of light emitted by them changes with time
C) The light from the star is scattered by the dust particles and air molecules in the earth's atmosphere D) The distance of the stars from the earth changes with time
 
Answer & Explanation Answer: A) The refractive index of the different layers of earth's atmosphere changes continuously, consequently the position of the star's image changes with time

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