Question # 1

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

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

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

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Metarial

Temperature

colour

Volume

Length

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

A black body is

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an ideal absorber

an ideal radiator

both of them

none of them

The concept of direction and position are purely

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absolute

relative

absolute or relative

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

Which one of the following physical quantities changes with relativistic speed

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Length

Mass

Time

All of the above

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

Compton derived an expression to find compton shift by applying to the process, the law of conservation of:

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Energy only

Momentum only

Mass only

Charge only

Both (A) and (B)

There is no way to detect:

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Absolute uniform motion

Accelerated motion

State rest

State of motion

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

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

When a platinum wire is heated, it appears white at

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1600°C

900°C

1100°C

1300°C

Compton studied the scattering of x-rays by loosely bound electrons from:

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NaCl crystal

Graphite crystal

Zirconia

Copper crystal

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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