Question # 1

The intensity of emitted energy (with wavelength) radiated from a black body at different temperatures was initially measured by:

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Lummer

Planck

Pringsheim

Both (A ) and (B)

Both (A) and (C)

The special theory of relativity is based on the

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one postulate

two postulates

three postulates

four postulates

When low energy photon interact with a metal,which of the following effect is likely to be taken place

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pair production

photoelectric

Compton effect

None of these

There is certain frequency below which no electrons are emitted from the metal surface, this frequency is known as

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maximum frequency

minimum frequency

threshold frequency

all of these

When a platinum wire is heated, it appears white at

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1600°C

900°C

1100°C

1300°C

The energy of the 4th orbit in hydrogen atom is

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2.5 ev

- 3.5 ev

-0.85 ev

-13.6 ev

A black body is

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an ideal absorber

an ideal radiator

both of them

none of them

Compton was awarded Nobel prize in physics in

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1921

1923

1925

1927

If a material object moves with the speed of light 'C' its mass becomes

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Equal to its rest mass

Four times of its rest mass

Double of its rest mass

Infinite

According to the de-Brogile relation, an object of large mass and ordinary speed has

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very small wavelength

very large wavelength

very small frequency

all of these

Due to relative motion of observer and the frame of reference of events, time always:

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Dilates itself

Contracts itself

Stretches itself

Both (A) and (C)

None of these

the symbol to be used in relativity problems denotes:

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Dilated time

Proper time

Life time

Half time

None of these

The existence of position was predicted by Dirace in

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1920

1925

1930

1928

An intertial frame of reference is a frame of reference which is

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at rest

moving with uniform velocity

either at rest or moving with uniform velocity

none of these

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

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1916

1919

1921

1923

When platinum wire is heated, it appears cherry red at

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1600°C

900°C

1100°C

1300°C

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