Question # 1

Photoelectrons are emitted when ultraviolet light falls on:

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Casium

Silver

Potassium

Any of these

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

the dilation of time applies to the timing processes which are:

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Physical

Chemical

Biological

All of these

None 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

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 bar 1.0 m in length and located along x-axix moves with a speed of 0.75 c with respect to a stationary observer. The length of the bar as measured by the stationary observer is

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1.66 m

1.0 m

0.66 m

2.66 m

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

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1916

1919

1921

1923

Strictly speaking, the earth is:

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An accelerated frame of reference

A non-inertial frame of reference

An inertial frame of reference

^{A non-accelerated frame of reference}

Both (A) and (B)

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

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pair production

photoelectric effect

Compton effect

None of these

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

de-Broglies hypthesis was experimentally verified by

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Maxwell

Compton

Einstein

Davison and Germer

The special theory of relatively treats the problems involving:

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Inertial frames of reference

Non-inertial frames

Non-accelerated frame

Botha (A) and (C)

Both (B) and (C)

The special theory of relativity treats problems invoving

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inertial frame of references

accelerating frame of references

both of these

none of these

Electromagnetic radiation or photons interact with matter in

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two distinct ways

three distinct ways

four distinct ways

five distinct ways

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

As compared to the distance measured by an observer on Earth, the distance from Earth to a star measured by an observer in a moving spaceship would seem:

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Smaller

Lerger

Same

Much larger

None of these

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

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