Question # 1

If a body reaches a speed equal to the speed of light, then its mass will became

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zero

very small

infinity

none of these

Wien's constant is measured in:

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Metre per kelviin

Metre kelvin

Kelvin per meter

Joules

Dynes

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

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 nature of radiations emitted by a hot body depends upon its:

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Metarial

Temperature

colour

Volume

Length

Position and momentum of a particle cannot both be measured simultaneously with perfect accuracy. This is the statement of

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photoelectric effect

pair production

Compton effect

uncertainty principle

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

Converse of pair production is known as

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Compton effect

annihilation of matter

photoelectric effect

none of these

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

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500°C

900°C

1100°C

1300°C

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

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

Intensity of light determines the:

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Energy of each photon

Number of photons

Speed of photons

Size of photons

None of these

A black body is

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an ideal absorber

an ideal radiator

both of them

none of them

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)

According to the Max plank, energy is redialed or absorbed in

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discrete packets

continuous waves

either of them

none of these

Victor de-Brogile received the Nobel prize in physics in

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1925

1929

1932

1935

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Physics ECAT Pre Engineering Chapter 19 Dawn of Modern Physics Physics Online Test MCQs With Answers

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