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

Question # 1

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 # 2

When platinum wire is heated, it appears cherry red at

1600°C A
900°C B
1100°C C
1300°C D

Question # 3

Compton shift refers to:

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

Question # 4

The Nobel Prize on the explanation of photoelectric effect was awarded to:

Max. Planck A
Maxwell B
Bohr C
Rutherford D
None of these E

Question # 5

Which one of the following physical quantities changes with relativistic speed

Length A
Mass B
Time C
All of the above D

Question # 6

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 # 7

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 # 8

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

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

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

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

2 mo A
1.67 mo B
0.67 mo C
2.67 mo D

Question # 11

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 # 12

If a material object moves with the speed of light 'C' its mass becomes

Equal to its rest mass A
Four times of its rest mass B
Double of its rest mass C
Infinite D

Question # 13

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 # 14

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 # 15

the symbol to be used in relativity problems denotes:

Dilated time A
Proper time B
Life time C
Half time D
None of these E

Question # 16

When a platinum wire is heated, it appears white at

1600°C A
900°C B
1100°C C
1300°C D

Question # 17

The special theory of relativity is based on the

one postulate A
two postulates B
three postulates C
four postulates D

Question # 18

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 # 19

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 # 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

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 # 22

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 # 23

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 # 24

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 # 25

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 # 26

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 # 27

At the temperature, a body emits radiation which is principally

of long wavelengths in the visible region A
of long wavelengths in the invisible infrared region B
of short wavelength in invisible ultraviolet region C
none of these D

Question # 28

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 # 29

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

Remains constant A
Decreases B
Increases to infinity C
Reduced to zero D

Question # 30

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

Sr.#	Question	Answer
1	The special theory of relativity is based on the	A. one postulate B. two postulates C. three postulates D. four postulates
2	de-Broglies hypthesis was experimentally verified by	A. Maxwell B. Compton C. Einstein D. Davison and Germer
3	The inside cavity of the black body is	A. painted white B. painted silver C. blackened with soot D. painted red
4	The year when A.H. compton was awarded Nobel Prize is:	A. 1923 B. 1927 C. 1931 D. 1935
5	Current, voltage, resistance measuring circuit is connected with the galvanometer with the help of switch, known as	A. ON switch B. off switch C. function switch D. none of these
6	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
7	According to Einstein, with the great increase in the speed of the body, the relativistic mass of the body	A. Remains constant B. Decreases C. Increases to infinity D. Reduced to zero
8	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
9	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
10	The energy of a photon is represented by	A. h/c² B. h/T C. hc² D. hf/c²

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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