Question # 1

Albert Einstein got the Nobel prize in physics for his explanation of photoelectric effect in

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1916

1919

1921

1923

In order to produce pair production, a photon must have a energy

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0.511 Me v

0.256 Me v

1.02 Me v

0.956 Me v

In the compton's effect, it is found that the wavelength of incident x-rays is

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greater than the wavelength of scattered x-rays

equal to the wavelength of scattered x-rays

less than the wavelength of scattered x-rays

any one of these

The threshold frequency of sodium is 6 x 10⁶MHz. The cut-off wavelength for this metal will be

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500 m

500 nm

500 km

500 cm

None of these

A black body is

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an ideal absorber

an ideal radiator

both of them

none of them

Converse of pair production is known as

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Compton effect

annihilation of matter

photoelectric effect

none of these

The value of threshold frequency for different metals is

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different

same

may be different or may be same

none of these

Compton derived an expression to find compton shift by applying to the process, the law of conservation of:

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Energy only

Momentum only

Mass only

Charge only

Both (A) and (B)

The energy of a photon in a beam of infrared radiation of wavelength 1240 nm is

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100 ev

10⁶e v

10³e v

1.0 e v

When platinum wire is heated, then at the temperature of 500 ^oC, it becomes:

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Yellow

Orange red

Dull red

White

Cherry red

When the atomic particle are moving with velocities approaching that of light:

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Newton's laws become valid

Relativistic effects become prominent

Botha(A) and (B) are valid

Neither (A)nor (B)

There mass becomes zero.

If you are moving at relativistic speed between two points that are a fixed distance apart, then the distance between the two points appers

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larger

shorter

equal

none of these

If the radius of first orbit of hydrogen atom is 0.53° A the radius of second orbit will be

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2.120°A

0.212°A

21.2°A

0.14°

a

There is no way to detect:

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Absolute uniform motion

Accelerated motion

State rest

State of motion

None of these

If A represents linear momentum and c, the velocity of light, then unit of pc in international system of units is:

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Newton

Joule

Joule-Sec

Joule-s^-1

Watt

S.I. unit of planks constant is

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J-s^-1

J.s

J.s^-2

J.s²

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