Question # 1

Victor de-Brogile received the Nobel prize in physics in

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1925

1929

1932

1935

In photoelectric effect the energy of ejected electrons depend on

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The frequency

The intensity

Both frequency and intensity

None of these

According to the special theory of relativity, a moving clock

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runs faster

runs slower

neither runs faster nor slower

all 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

When a position comes close to an electron they annihilate into

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one photon

two photons which travel in the same direction

two photons which travels in the opposite direction

two photons which travel in any direction

When a platinum wire is heated, it appears white at

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1600°C

900°C

1100°C

1300°C

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

The concept of direction is purely:

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Absolute

Relative

Relative to stars always

Relative to the sun always

None of these

The year when A.H. compton was awarded Nobel Prize is:

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1923

1927

1931

1935

None of these

According to the electromagnetic wave theory of light, increasing the intensity of incident light should increase the

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number of photoelectrons

size of the photoelectrons

charge on photoelectrons

K.E of photoelectrons

When platinum wire is heated, it appears cherry red at

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1600°C

900°C

1100°C

1300°C

An electron is accelerated through a potential difference of 50v. its de-Brogile wavelength is

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1.66 x 10^-29m

1.74 x 10^-10cm

17.4 x 10^-6m

1.74 x 10^-10m

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 a platinum wire is heated, it appears yellow at

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1600°C

900°C

1100°C

1300°C

There is no way to detect:

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Absolute uniform motion

Accelerated motion

State rest

State of motion

None of these

The Stephen-Boltzmann law for the black body radiation is given by

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E = T²

E = -T²

E = T⁴

E = -T⁴

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