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

Question # 1

The concept of direction is purely:

Absolute A
Relative B
Relative to stars always C
Relative to the sun always D
None of these E

Question # 2

The energy of the 4th orbit in hydrogen atom is

2.5 ev A
- 3.5 ev B
-0.85 ev C
-13.6 ev D

Question # 3

According to the special theory of relativity, a moving clock

runs faster A
runs slower B
neither runs faster nor slower C
all of these D

Question # 4

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

1.66 m A
1.66 x 10^-10m B
1.66 x 10^-29cm C
1.66 x 10^-29m D

Question # 5

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 # 6

The inside cavity of the black body is

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

Question # 7

de-Broglies hypthesis was experimentally verified by

Maxwell A
Compton B
Einstein C
Davison and Germer D

Question # 8

Momentum is a parameter associated with

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

Question # 9

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

particular metal surface A
frequency of incident light B
both of them C
none of them D

Question # 10

In photoelectric effect the energy of ejected electrons depend on

The frequency A
The intensity B
Both frequency and intensity C
None of these D

Question # 11

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 # 12

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

photoelectric effect A
pair production B
Compton effect C
uncertainty principle D

Question # 13

Max plank received the Nobel Prize in physics for his discovery of energy quanta in

1900 A
1906 B
1912 C
1918 D

Question # 14

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

very small wavelength A
very large wavelength B
very small frequency C
all of these D

Question # 15

An inertial frame is that frame in which

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

Question # 16

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 # 17

Photoelectric effect takes place with a photon of:

Very high energy A
Very low energy B
Low energy C
High energy D
None of these E

Question # 18

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 # 19

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 # 20

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 # 21

The energy of a photon is represented by

h/c² A
h/T B
hc² C
hf/c² D

Question # 22

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:

Smaller A
Lerger B
Same C
Much larger D
None of these E

Question # 23

0.1 kg mass will be equivalent to the energy

9 x 10¹⁵J A
5 x 10⁸J B
6 x 10¹⁶J C
9 x 10^-16J D

Question # 24

Compton was awarded Nobel prize in physics in

1921 A
1923 B
1925 C
1927 D

Question # 25

The existence of position was predicted by Dirace in

1920 A
1925 B
1930 C
1928 D

Question # 26

A photon is considered to have

Momentum A
Energy B
Wavelength C
All of the above D

Question # 27

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

Wavelength A
Frequency B
Energy C
Temperature D
All of these E

Question # 28

The whole shape of the black body spectrum for all wavelengths was explained by the formula proposed by

Max plank A
Newton B
Einstein C
J.J. Thomson D

Question # 29

The speed of a pendulum is measured to be 3.0 s in the inertial reference frame of the pendulum. What is its period measured by an observer moving at a speed of 0.95 c with respect to the pendulum

2.9 s A
3.0 s B
6.6 s C
9.6 s D

Question # 30

Which one of the following physical quantities changes with relativistic speed

Length A
Mass B
Time C
All of the above D

Sr.#	Question	Answer
1	The positron was discovered by:	A. In cosmic radiation B. In 1932 C. By Carl Anderson D. All above
2	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
3	A particle having mass and charge equal to that of an electron is called:	A. Proton B. Positron C. Pion D. Pi-meson
4	According to the de-Brogile relation, an object of large mass and ordinary speed has	A. very small wavelength B. very large wavelength C. very small frequency D. all of these
5	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:	A. Smaller B. Lerger C. Same D. Much larger
6	Intensity of light determines the:	A. Energy of each photon B. Number of photons C. Speed of photons D. Size of photons
7	In photoelectric effect the energy of ejected electrons depend on	A. The frequency B. The intensity C. Both frequency and intensity D. None of these
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	G.P. Thomson observer experimentally that electrons and neutrons possess	A. particle-like properties B. wave-like properties C. neither particle nor wave like properties D. none of these
10	When monochromatic light is allowed to fall on cathode, it begins to emit electrons, these electrons are called	A. thermoionic electrons B. free electrons C. photoelectrons D. slow electrons

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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