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

Question # 1

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 # 2

According to the Max plank, energy is redialed or absorbed in

discrete packets A
continuous waves B
either of them C
none of these D

Question # 3

When platinum wire is heated, it appears cherry red at

1600°C A
900°C B
1100°C C
1300°C D

Question # 4

S.I. unit of planks constant is

J-s^-1 A
J.s B
J.s^-2 C
J.s² D

Question # 5

Which of the following is not an example of intertial frame

a body placed on the surface of earth A
a body placed in a car moving with uniform velocity B
a body placed in a car moving with same acceleration C
none of these D

Question # 6

The existence of position was predicted by Dirace in

1920 A
1925 B
1930 C
1928 D

Question # 7

A black body is

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

Question # 8

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 # 9

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 # 10

When a platinum wire is heated, it appears orange red at

500°C A
900°C B
1100°C C
1300°C D

Question # 11

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 # 12

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 # 13

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 # 14

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 # 15

Which one of the following physical quantities changes with relativistic speed

Length A
Mass B
Time C
All of the above D

Question # 16

An inertial frame is that frame in which

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

Question # 17

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 # 18

The analysis of the distribution of wavelengths of the radiation emitted from a hot body set the foundation of new mechanics, known as

classical mechanics A
Newtonian mechanics B
quantum mechanics C
statistical mechanics D

Question # 19

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 # 20

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 # 21

Compton shift refers to:

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

Question # 22

The ratio of energy E to the corresponding frequency (f) of the radiation (emitted or absorbed) is called:

Wien's constant A
Stefen's constnat B
Planck's constant C
Boltzmann's constant D
None of these E

Question # 23

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 # 24

When a platinum wire is heated, it appears white at

1600°C A
900°C B
1100°C C
1300°C D

Question # 25

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 # 26

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 # 27

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 # 28

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 # 29

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 # 30

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

Sr.#	Question	Answer
1	An electron is accelerated through a potential difference of 50v. its de-Brogile wavelength is	A. 1.66 x 10^-29m B. 1.74 x 10^-10cm C. 17.4 x 10^-6m D. 1.74 x 10^-10m
2	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
3	Max plank founded a mathematical model resulting in an equation that describes the shape of observed black body radiation curves exactly, in	A. 1890 B. 1895 C. 1900 D. 1905
4	Photoelectric effect takes place with a photon of:	A. Very high energy B. Very low energy C. Low energy D. High energy
5	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)
6	The analysis of the distribution of wavelengths of the radiation emitted from a hot body set the foundation of new mechanics, known as	A. classical mechanics B. Newtonian mechanics C. quantum mechanics D. statistical mechanics
7	When a platinum wire is heated, it appears white at	A. 1600°C B. 900°C C. 1100°C D. 1300°C
8	The mass 'm' of a body moving at 0.8 c (whose rest mass is mo) becomes	A. 2 mo B. 1.67 mo C. 0.67 mo D. 2.67 mo
9	The concept of direction is purely:	A. Absolute B. Relative C. Relative to stars always D. Relative to the sun always
10	The value of the Stephen's constant for black body radiations is given by	A. 5.6 x 10⁸Wm^-2K^-4 B. 5.67 x 10^-8Wm^-2K^-4 C. 2.9 x 10^-3mK D. 2.9 x 10³mK

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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