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

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ECAT Pre General Science Physics Chapter 19 Dawn of Modern Physics

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Question # 1

Electromagnetic -radiation means:

Question # 2

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

Question # 3

The energy of photon 'E' is proported to

Question # 4

A particle having mass and charge equal to that of an electron is called:

Question # 5

The value of the plank's constant 'h' is given by

Question # 6

A black body is

Question # 7

Photoelectrons are emitted when ultraviolet light falls on:

Question # 8

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

Question # 9

A particle of mass 5.0 mg moves with a speed of 8.0 m/s. Its de-Brogile wavelength is

Question # 10

The concept of direction is purely:

Question # 11

An electron is accelerated through a potential difference of 50v. its de-Brogile wavelength is

Question # 12

Victor de-Brogile received the Nobel prize in physics in

Question # 13

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

Question # 14

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

Question # 15

Practically the quantity v/c is always:

Question # 16

The positron was discovered by:

Question # 17

The year when A.H. compton was awarded Nobel Prize is:

Question # 18

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

Question # 19

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

Question # 20

Photoelectric effect takes place with a photon of:

Question # 21

From the theory of relativity, momentum p of the photon is related to energy as

Question # 22

A photon is considered to have

Question # 23

At the temperature, a body emits radiation which is principally

Question # 24

When a platinum wire is heated, it appears yellow at

Question # 25

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

Question # 26

The Nobel Prize on the explanation of photoelectric effect was awarded to:

Question # 27

There is no way to detect:

Question # 28

Which one of the following physical quantities changes with relativistic speed

Question # 29

S.I. unit of planks constant is

Question # 30

In photoelectric effect the energy of ejected electrons depend on

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ECAT Physics Chapter 19 Important MCQ's

Sr.# Question Answer
1 The stopping voltage for a certain metal is 100 volts, then the work function for the cathode plate is
A. 100 J
B. 1.6 x 10-17J
C. 100 eV
D. 1.6 x 10-17eV
2 The unit of work function is:
A. Joule
B. Electron volt
C. That of threshold frequency
D. Both (A) and (B)
3 Practically the quantity v/c is always:
A. less than one
B. Equal to one
C. Greater then one
D. all of these
4 S.I. unit of planks constant is
A. J-s-1
B. J.s
C. J.s-2
D. J.s2
5 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
6 The value of threshold frequency for different metals is
A. different
B. same
C. may be different or may be same
D. none of these
7 Max plank founded a mathematical model resulting in an equation that describes the shape of observed black body radiation curves exactly, in
A. 1890
B. 1895
C. 1900
D. 1905
8 When a position comes close to an electron they annihilate into photons such that
A. each photon has energy 0.51 Me v
B. each photon has energy 1.02 Me v
C. each photon has energy 0.25 Me v
D. none of these
9 Compton was awarded Nobel prize in physics in
A. 1921
B. 1923
C. 1925
D. 1927
10 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

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