ECAT Pre General Science Physics Chapter 19 MCQ Test With Answer

MCQ's Test For ECAT Pre General Science Physics Chapter 19 Dawn of Modern Physics

Try The MCQ's Test For ECAT Pre General Science Physics Chapter 19 Dawn of Modern Physics

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ECAT Pre General Science Physics Chapter 19 Dawn of Modern Physics

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Question # 1

In the compton's effect, it is found that the wavelength of incident x-rays is

Question # 2

The special theory of relativity treats problems invoving

Question # 3

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

Question # 4

Which one of the following physical quantities changes with relativistic speed

Question # 5

Practically the quantity v/c is always:

Question # 6

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

Question # 7

An intertial frame of reference is a frame of reference which is

Question # 8

With the help of 50 K v electron microscope, a resolution of

Question # 9

Compton was awarded Nobel prize in physics in

Question # 10

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:

Question # 11

The unit of work function is:

Question # 12

The inside cavity of the black body is

Question # 13

The energy of a photon is represented by

Question # 14

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

Question # 15

The threshold frequency of sodium is 6 x 106MHz. The cut-off wavelength for this metal will be

Question # 16

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

Question # 17

The emission of electrons from a metal surface when exposed to light of suitable frequency is called the

Question # 18

As the light shines on the metal surface, the electrons are ejected

Question # 19

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

Question # 20

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

Question # 21

Photocell is a device which converts

Question # 22

Strictly speaking, the earth is:

Question # 23

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

Question # 24

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

Question # 25

S.I. unit of planks constant is

Question # 26

Pair production is the phenomenon in which

Question # 27

Compton shift refers to:

Question # 28

The Einstein's changes in length, mass and time are not observed in common life because

Question # 29

In order to produce pair production, a photon must have a energy

Question # 30

Position was discovered by Carl Anderson in

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ECAT Physics Chapter 19 Important MCQ's

Sr.# Question Answer
1 A particle of mass 5.0 mg moves with a speed of 8.0 m/s. Its de-Brogile wavelength is
A. 1.66 m
B. 1.66 x 10-10m
C. 1.66 x 10-29cm
D. 1.66 x 10-29m
2 Absolute motion cannot be detected
A. in its own frame of references
B. in a different frame of references
C. both in its frame and different frame of references
D. none of these
3 The concept of direction and position are purely
A. absolute
B. relative
C. absolute or relative
D. none of these
4 The photon of radio-waves has energy of about
A. 1 Me V
B. 1 Ke v
C. 10-10e v
D. 1010e v
5 The analysis of the distribution of wavelengths of the radiation emitted from a hot body set the foundation of new mechanics, known as
A. classical mechanics
B. Newtonian mechanics
C. quantum mechanics
D. statistical mechanics
6 An electron is accelerated through a potential difference of 50v. its de-Brogile wavelength is
A. 1.66 x 10-29m
B. 1.74 x 10-10cm
C. 17.4 x 10-6m
D. 1.74 x 10-10m
7 In the compton's effect, it is found that the wavelength of incident x-rays is
A. greater than the wavelength of scattered x-rays
B. equal to the wavelength of scattered x-rays
C. less than the wavelength of scattered x-rays
D. any one of these
8 Victor de-Brogile received the Nobel prize in physics in
A. 1925
B. 1929
C. 1932
D. 1935
9 The mass 'm' of a body moving at 0.8 c (whose rest mass is mo) becomes
A. 2 mo
B. 1.67 mo
C. 0.67 mo
D. 2.67 mo
10 The nature of radiations emitted by a hot body depends upon its:
A. Metarial
B. Temperature
C. colour
D. Volume

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