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

Question # 1

When a position comes close to an electron they annihilate into

one photon A
two photons which travel in the same direction B
two photons which travels in the opposite direction C
two photons which travel in any direction D

Question # 2

A black body is

an ideal absorber A
an ideal radiator B
both of them C
none of them D

Question # 3

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

We dont observer then seriously A
The masses are too large B
Their speed is too small than the speed of right C
All of the above D

Question # 4

Electromagnetic -radiation means:

Photons A
protons B
Electrons C
Mesons D
None of these E

Question # 5

Albert Einstein got the Nobel prize in physics for his explanation of photoelectric effect in

1916 A
1919 B
1921 C
1923 D

Question # 6

There is no way to detect:

Absolute uniform motion A
Accelerated motion B
State rest C
State of motion D
None of these E

Question # 7

The energy of a photon in a beam of infrared radiation of wavelength 1240 nm is

100 ev A
10⁶e v B
10³e v C
1.0 e v D

Question # 8

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

1.66 m A
1.0 m B
0.66 m C
2.66 m D

Question # 9

The energy of photon 'E' is proported to

The magnetic field H A
The electric field E B
Both the electric and magnetic field H and E C
Frequency 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

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 # 12

An intertial frame of reference is a frame of reference which is

at rest A
moving with uniform velocity B
either at rest or moving with uniform velocity C
none of these D

Question # 13

Absolute motion cannot be detected

in its own frame of references A
in a different frame of references B
both in its frame and different frame of references C
none of these D

Question # 14

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

Proton A
Positron B
Pion C
Pi-meson D
Both (C) and (D) E

Question # 15

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 # 16

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 # 17

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 # 18

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 # 19

Photocell is a device which converts

chemical energy into electrical energy A
electrical energy into light energy B
heat energy into electrical energy C
light energy into electrical energy D

Question # 20

Current, voltage, resistance measuring circuit is connected with the galvanometer with the help of switch, known as

ON switch A
off switch B
function switch C
none of these D

Question # 21

The general theory of relativity treats problems involving

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

Question # 22

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 # 23

The energy of a photon is represented by

h/c² A
h/T B
hc² C
hf/c² D

Question # 24

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 # 25

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 # 26

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 # 27

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 # 28

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 # 29

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 # 30

Photoelectrons are emitted when ultraviolet light falls on:

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

Sr.#	Question	Answer
1	The emission of electrons from a metal surface when exposed to light of suitable frequency is called the	A. pair production B. Compton effect C. photoelectric effect D. relativity
2	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
3	Max plank received the Nobel Prize in physics for his discovery of energy quanta in	A. 1900 B. 1906 C. 1912 D. 1918
4	Wien's constant is measured in:	A. Metre per kelviin B. Metre kelvin C. Kelvin per meter D. Joules
5	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
6	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
7	If you are moving at relativistic speed between two points that are a fixed distance apart, then the distance between the two points appers	A. larger B. shorter C. equal D. none of these
8	Due to relative motion of observer and the frame of reference of events, time always:	A. Dilates itself B. Contracts itself C. Stretches itself D. Both (A) and (C)
9	The energy of a photon is represented by	A. h/c² B. h/T C. hc² D. hf/c²
10	The energy of photon 'E' is proported to	A. The magnetic field H B. The electric field E C. Both the electric and magnetic field H and E D. Frequency

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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