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

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

Question # 2

When a platinum wire is heated, it appears dull red at about

Question # 3

When a position comes close to an electron they annihilate into

Question # 4

There is no way to detect:

Question # 5

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

Question # 6

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

Question # 7

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

Question # 8

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

Question # 9

The ratio of energy E to the corresponding frequency (f) of the radiation (emitted or absorbed) is called:

Question # 10

Practically the quantity v/c is always:

Question # 11

When platinum wire is heated, then at the temperature of 500 oC, it becomes:

Question # 12

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

Question # 13

The photon of radio-waves has energy of about

Question # 14

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

Question # 15

The way through which electromagnetic radiations or photons interact with matter depends upon their:

Question # 16

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

Question # 17

An inertial frame is that frame in which

Question # 18

The unit of work function is:

Question # 19

The special theory of relativity is based on:

Question # 20

Photoelectrons are emitted when ultraviolet light falls on:

Question # 21

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

Question # 22

A black body is

Question # 23

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

Question # 24

Pair production is the phenomenon in which

Question # 25

S.I. unit of planks constant is

Question # 26

Photoelectric effect takes place with a photon of:

Question # 27

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

Question # 28

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

Question # 29

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

Question # 30

If a body reaches a speed equal to the speed of light, then its mass will became

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ECAT Physics Chapter 19 Important MCQ's

Sr.# Question Answer
1 There is certain frequency below which no electrons are emitted from the metal surface, this frequency is known as
A. maximum frequency
B. minimum frequency
C. threshold frequency
D. all of these
2 Which one of the following physical quantities changes with relativistic speed
A. Length
B. Mass
C. Time
D. All of the above
3 An inertial frame is that frame in which
A. a>0
B. a=0
C. a<0
D. none of these
4 Which of the following phenomenon proves the particle nature of light
A. interference
B. diffraction
C. photoelectric effect
D. none of these
5 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
A. 1.66 m
B. 1.0 m
C. 0.66 m
D. 2.66 m
6 Compton studied the scattering of x-rays by loosely bound electrons from:
A. NaCl crystal
B. Graphite crystal
C. Zirconia
D. Copper crystal
7 The mass of an object will be doubled at speed
A. 1.6 x 108ms-1
B. 2.6 X 108ms-1
C. 2.6 x 107ms-1
D. 2.6 x 109ms-1
8 Pair production is the phenomenon in which
A. matter is converted into energy
B. energy is converted into matter
C. light is converted into electrical energy
D. electrical energy is converted into light
9 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
10 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

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