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

Question # 1

Position was discovered by Carl Anderson in

1920 A
1925 B
1928 C
1932 D

Question # 2

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

0.511 Me v A
0.256 Me v B
1.02 Me v C
0.956 Me v D

Question # 3

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 # 4

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 # 5

The Stephen-Boltzmann law for the black body radiation is given by

E = T² A
E = -T² B
E = T⁴ C
E = -T⁴ D

Question # 6

Strictly speaking, the earth is:

An accelerated frame of reference A
A non-inertial frame of reference B
An inertial frame of reference C
^{A non-accelerated frame of reference} D
Both (A) and (B) E

Question # 7

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

greater than the wavelength of scattered x-rays A
equal to the wavelength of scattered x-rays B
less than the wavelength of scattered x-rays C
any one of these D

Question # 8

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

each photon has energy 0.51 Me v A
each photon has energy 1.02 Me v B
each photon has energy 0.25 Me v C
none of these D

Question # 9

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 # 10

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

1900 A
1906 B
1912 C
1918 D

Question # 11

Photoelectrons are emitted when ultraviolet light falls on:

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

Question # 12

Converse of pair production is known as

Compton effect A
annihilation of matter B
photoelectric effect C
none of these D

Question # 13

Which one of the following physical quantities changes with relativistic speed

Length A
Mass B
Time C
All of the above D

Question # 14

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

Metarial A
Temperature B
colour C
Volume D
Length E

Question # 15

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 # 16

Compton shift refers to:

Photon A
Meson B
Proton C
Positron D
Both (B) and (D) E

Question # 17

The value of the Stephen's constant for black body radiations is given by

5.6 x 10⁸Wm^-2K^-4 A
5.67 x 10^-8Wm^-2K^-4 B
2.9 x 10^-3mK C
2.9 x 10³mK D

Question # 18

Electromagnetic -radiation means:

Photons A
protons B
Electrons C
Mesons D
None of these 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

In process of annihilation of matter, the two photons produced move in opposite direction to converse

momentum A
charge B
energy C
mass D

Question # 21

The special theory of relativity treats problems invoving

inertial frame of references A
accelerating frame of references B
both of these C
none of these D

Question # 22

G.P. Thomson observer experimentally that electrons and neutrons possess

particle-like properties A
wave-like properties B
neither particle nor wave like properties C
none of these D

Question # 23

When a platinum wire is heated, it appears yellow at

1600°C A
900°C B
1100°C C
1300°C D

Question # 24

There is certain frequency below which no electrons are emitted from the metal surface, this frequency is known as

maximum frequency A
minimum frequency B
threshold frequency C
all of these D

Question # 25

Victor de-Brogile received the Nobel prize in physics in

1925 A
1929 B
1932 C
1935 D

Question # 26

The mass of an object will be doubled at speed

1.6 x 10⁸ms^-1 A
2.6 X 10⁸ms^-1 B
2.6 x 10⁷ms^-1 C
2.6 x 10⁹ms^-1 D

Question # 27

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 # 28

Which of the following phenomenon proves the particle nature of light

interference A
diffraction B
photoelectric effect C
none of these D

Question # 29

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 # 30

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

0.5 to 1 m to possible A
1 m to 10 m is possible B
0.5 to 1 nm is possible C
1 to 10 nm is possible D

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	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
3	At the temperature, a body emits radiation which is principally	A. of long wavelengths in the visible region B. of long wavelengths in the invisible infrared region C. of short wavelength in invisible ultraviolet region D. none of these
4	Position and momentum of a particle cannot both be measured simultaneously with perfect accuracy. This is the statement of	A. photoelectric effect B. pair production C. Compton effect D. uncertainty principle
5	When a position comes close to an electron they annihilate into	A. one photon B. two photons which travel in the same direction C. two photons which travels in the opposite direction D. two photons which travel in any direction
6	The special theory of relatively treats the problems involving:	A. Inertial frames of reference B. Non-inertial frames C. Non-accelerated frame D. Botha (A) and (C)
7	The length contraction happens only	A. Opposite to the direction of motion B. along the direction of motion C. perpendicular to the direction of motion D. In any direction
8	When a platinum wire is heated, it appears dull red at about	A. 500°C B. 900°C C. 1100°C D. 1300°C
9	With the help of 50 K v electron microscope, a resolution of	A. 0.5 to 1 m to possible B. 1 m to 10 m is possible C. 0.5 to 1 nm is possible D. 1 to 10 nm is possible
10	The unit of work function is:	A. Joule B. Electron volt C. That of threshold frequency D. Both (A) and (B)

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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