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

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

Question # 2

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

Question # 3

If you are moving at relativistic speed between two points that are a fixed distance apart, then the distance between the two points appers

Question # 4

When a position comes close to an electron they annihilate into photons such that

Question # 5

S.I. unit of planks constant is

Question # 6

The energy of the 4th orbit in hydrogen atom is

Question # 7

The value of threshold frequency for different metals is

Question # 8

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

Question # 9

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

Question # 10

When a platinum wire is heated, it appears white at

Question # 11

According to the de-Brogile relation, an object of large mass and ordinary speed has

Question # 12

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

Question # 13

Compton shift refers to:

Question # 14

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

Question # 15

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

Question # 16

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

Question # 17

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

Question # 18

The energy of a photon in a beam of infrared radiation of wavelength 1240 nm is

Question # 19

Which one of the following physical quantities changes with relativistic speed

Question # 20

Photoelectrons are emitted when ultraviolet light falls on:

Question # 21

The photoelectric effect, the maximum energy of photoelectrons depends on the

Question # 22

If A represents linear momentum and c, the velocity of light, then unit of pc in international system of units is:

Question # 23

According to the special theory of relativity

Question # 24

The analysis of the distribution of wavelengths of the radiation emitted from a hot body set the foundation of new mechanics, known as

Question # 25

The energy of photon 'E' is proported to

Question # 26

Due to relative motion of observer and the frame of reference of events, time always:

Question # 27

Electromagnetic -radiation means:

Question # 28

The photon of radio-waves has energy of about

Question # 29

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

Question # 30

When a platinum wire is heated, it appears yellow at

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ECAT Physics Chapter 19 Important MCQ's

Sr.# Question Answer
1 According to Einstein, with the great increase in the speed of the body the relativistic length of the body
A. Remains constant
B. Decreases
C. Increases
D. Reduces to zero
2 The Nobel Prize on the explanation of photoelectric effect was awarded to:
A. Max. Planck
B. Maxwell
C. Bohr
D. Rutherford
3 According to the special theory of relativity
A. mass and energy are same entities
B. mass and energy are same entities but interconverible
C. mass and energy are different entities but interconverible
D. mass and energy are different entities but non-interconveritble
4 According to the Max plank, energy is redialed or absorbed in
A. discrete packets
B. continuous waves
C. either of them
D. none of these
5 If A represents linear momentum and c, the velocity of light, then unit of pc in international system of units is:
A. Newton
B. Joule
C. Joule-Sec
D. Joule-s-1
6 When a platinum wire is heated, it appears white at
A. 1600°C
B. 900°C
C. 1100°C
D. 1300°C
7 In process of annihilation of matter, the two photons produced move in opposite direction to converse
A. momentum
B. charge
C. energy
D. mass
8 The unit of work function is:
A. Joule
B. Electron volt
C. That of threshold frequency
D. Both (A) and (B)
9 If the radius of first orbit of hydrogen atom is 0.53° A the radius of second orbit will be
A. 2.120°A
B. 0.212°A
C. 21.2°A
D. 0.14°
a
10 Intensity of light determines the:
A. Energy of each photon
B. Number of photons
C. Speed of photons
D. Size of photons

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