Question # 1

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

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E = T²

E = -T²

E = T⁴

E = -T⁴

The value of the Stephen's constant for black body radiations is given by

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5.6 x 10⁸Wm^-2K^-4

5.67 x 10^-8Wm^-2K^-4

2.9 x 10^-3mK

2.9 x 10³mK

Photoelectrons are emitted when ultraviolet light falls on:

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Casium

Silver

Potassium

Any of these

None of these

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

The length contraction happens only

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Opposite to the direction of motion

along the direction of motion

perpendicular to the direction of motion

In any direction

Max plank received the Nobel Prize in physics for his discovery of energy quanta in

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1900

1906

1912

1918

The photon of radio-waves has energy of about

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1 Me V

1 Ke v

10^-10e v

10¹⁰e v

Victor de-Brogile received the Nobel prize in physics in

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1925

1929

1932

1935

S.I. unit of planks constant is

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J-s^-1

J.s

J.s^-2

J.s²

The way through which electromagnetic radiations or photons interact with matter depends upon their:

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Wavelength

Frequency

Energy

Temperature

All of these

The special theory of relativity is based on:

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Four postulates

Three postulates

Two postulates

One postulate

None of these

When monochromatic light is allowed to fall on cathode, it begins to emit electrons, these electrons are called

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thermoionic electrons

free electrons

photoelectrons

slow electrons

Compton shift refers to:

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Photon

Meson

Proton

Positron

Both (B) and (D)

According to Einstein, with the great increase in the speed of the body the relativistic length of the body

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Remains constant

Decreases

Increases

Reduces to zero

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

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

The stopping voltage for a certain metal is 100 volts, then the work function for the cathode plate is

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100 J

1.6 x 10^-17J

100 eV

1.6 x 10^-17eV

The mass 'm' of a body moving at 0.8 c (whose rest mass is mo) becomes

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2 mo

1.67 mo

0.67 mo

2.67 mo

Max plank founded a mathematical model resulting in an equation that describes the shape of observed black body radiation curves exactly, in

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1890

1895

1900

1905

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)

When a platinum wire is heated, it appears orange red at

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500°C

900°C

1100°C

1300°C

Electromagnetic -radiation means:

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Photons

protons

Electrons

Mesons

None of these

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

The positron was discovered by:

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In cosmic radiation

In 1932

By Carl Anderson

All above

By direc

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

The general theory of relativity treats problems involving

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inertial frame of references

accelerating frame of references

both of these

none of these

From the theory of relativity, momentum p of the photon is related to energy as

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p = hfc

p = hf/c

p = f(hc,f)

p = cf/h

According to the special theory of relativity

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mass and energy are same entities

mass and energy are same entities but interconverible

mass and energy are different entities but interconverible

mass and energy are different entities but non-interconveritble

The existence of position was predicted by Dirace in

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1920

1925

1930

1928

The ratio of energy E to the corresponding frequency (f) of the radiation (emitted or absorbed) is called:

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Wien's constant

Stefen's constnat

Planck's constant

Boltzmann's constant

None of these

Converse of pair production is known as

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Compton effect

annihilation of matter

photoelectric effect

none of these

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