ECAT Pre General Science Chapter 19 online mcq test with answers for Physics chapter 19 (Dawn of Modern Physics)

Question # 1

Intensity of light determines the:

Energy of each photon A
Number of photons B
Speed of photons C
Size of photons D
None of these E

Question # 2

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

Newton A
Joule B
Joule-Sec C
Joule-s^-1 D
Watt E

Question # 3

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

100 J A
1.6 x 10^-17J B
100 eV C
1.6 x 10^-17eV D

Question # 4

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

1.6 x 10^-19J A
1.67 x 10^-27Kg B
6.63 x 10³⁴Js C
6.63 x 10^-34Js D

Question # 5

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

pair production A
photoelectric effect B
Compton effect C
None of these D

Question # 6

The inside cavity of the black body is

painted white A
painted silver B
blackened with soot C
painted red D

Question # 7

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

1923 A
1927 B
1931 C
1935 D
None of these E

Question # 8

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

500°C A
900°C B
1100°C C
1300°C D

Question # 9

The length contraction happens only

Opposite to the direction of motion A
along the direction of motion B
perpendicular to the direction of motion C
In any direction D

Question # 10

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

Energy only A
Momentum only B
Mass only C
Charge only D
Both (A) and (B) E

Question # 11

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

larger A
shorter B
equal C
none of these D

Question # 12

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

p = hfc A
p = hf/c B
p = f(hc,f) C
p = cf/h D

Question # 13

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

Physical A
Chemical B
Biological C
All of these D
None of these E

Question # 14

An inertial frame is that frame in which

a>0 A
a=0 B
a<0 C
none of these D

Question # 15

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

pair production A
Compton effect B
photoelectric effect C
relativity D

Question # 16

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

thermoionic electrons A
free electrons B
photoelectrons C
slow electrons D

Question # 17

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

slowly A
instantaneously B
either of these C
none of these D

Question # 18

The special theory of relatively treats the problems involving:

Inertial frames of reference A
Non-inertial frames B
Non-accelerated frame C
Botha (A) and (C) D
Both (B) and (C) E

Question # 19

If the radius of first orbit of hydrogen atom is 0.53° A the radius of second orbit will be

2.120°A A
0.212°A B
21.2°A C
0.14°
a
D

Question # 20

The concept of direction and position are purely

absolute A
relative B
absolute or relative C
none of these D

Question # 21

The energy of a photon is represented by

h/c² A
h/T B
hc² C
hf/c² D

Question # 22

Newton's law of motion do not hold in

an accelerated frame of reference A
an unaccelerated frame of reference B
both of these C
none of these D

Question # 23

Max Planck received the Nobel Prize for his discovery of energy quants in:

1718 AD A
1918 AH B
1818 AD C
1918 AD D
None of these E

Question # 24

Photoelectrons are emitted when ultraviolet light falls on:

Casium A
Silver B
Potassium C
Any of these D
None of these E

Question # 25

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

Dilates itself A
Contracts itself B
Stretches itself C
Both (A) and (C) D
None of these E

Question # 26

Which one of the following physical quantities changes with relativistic speed

Length A
Mass B
Time C
All of the above D

Question # 27

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

zero A
very small B
infinity C
none of these D

Question # 28

Compton was awarded Nobel prize in physics in

1921 A
1923 B
1925 C
1927 D

Question # 29

Momentum is a parameter associated with

wave motion A
particle motion B
neither wave nor particle motion C
none of these D

Question # 30

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

Metarial A
Temperature B
colour C
Volume D
Length E

Sr.#	Question	Answer
1	The concept of direction is purely:	A. Absolute B. Relative C. Relative to stars always D. Relative to the sun always
2	A high temperature, the proportion of shorter wavelengths radiation, emitted by the body	A. decreases B. first increases then decreases C. increases D. any one of them
3	When low energy photon interact with a metal,which of the following effect is likely to be taken place	A. pair production B. photoelectric C. Compton effect D. None of these
4	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
5	If a body reaches a speed equal to the speed of light, then its mass will became	A. zero B. very small C. infinity D. none of these
6	A photon is considered to have	A. Momentum B. Energy C. Wavelength D. All of the above
7	The value of the plank's constant 'h' is given by	A. 1.6 x 10^-19J B. 1.67 x 10^-27Kg C. 6.63 x 10³⁴Js D. 6.63 x 10^-34Js
8	Intensity of light determines the:	A. Energy of each photon B. Number of photons C. Speed of photons D. Size of photons
9	the dilation of time applies to the timing processes which are:	A. Physical B. Chemical C. Biological D. All of these
10	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

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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

ECAT Pre General Science Physics Chapter 19 Dawn of Modern Physics