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

Question # 1

The threshold frequency of sodium is 6 x 10⁶MHz. The cut-off wavelength for this metal will be

500 m A
500 nm B
500 km C
500 cm D
None of these E

Question # 2

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 # 3

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 # 4

Wave nature of particle was proposed by

Einstein A
Plank B
De-Brogile C
Max well D

Question # 5

According to the special theory of relativity, time is

absolute quantity A
not absolute quantity B
constant quantity C
none of these D

Question # 6

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 # 7

A high temperature, the proportion of shorter wavelengths radiation, emitted by the body

decreases A
first increases then decreases B
increases C
any one of them D

Question # 8

Compton shift refers to:

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

Question # 9

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

Question # 10

An inertial frame is that frame in which

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

Question # 11

When a platinum wire is heated, it appears yellow at

1600°C A
900°C B
1100°C C
1300°C D

Question # 12

According to the electromagnetic wave theory of light, increasing the intensity of incident light should increase the

number of photoelectrons A
size of the photoelectrons B
charge on photoelectrons C
K.E of photoelectrons D

Question # 13

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

Metarial A
Temperature B
colour C
Volume D
Length E

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

Converse of pair production is known as

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

Question # 16

When low energy photon interact with a metal,which of the following effect is likely to be taken place

pair production A
photoelectric B
Compton effect C
None of these D

Question # 17

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

Remains constant A
Decreases B
Increases C
Reduces to zero D

Question # 18

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 # 19

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 # 20

A non-inertial frame of reference is one, in which

law of inertial is valid A
all laws of physics are the same in all frames B
a>0 or a<0 C
a=0 D

Question # 21

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 # 22

Which one of the following physical quantities changes with relativistic speed

Length A
Mass B
Time C
All of the above D

Question # 23

According to the special theory of relativity

mass and energy are same entities A
mass and energy are same entities but interconverible B
mass and energy are different entities but interconverible C
mass and energy are different entities but non-interconveritble D

Question # 24

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 # 25

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 # 26

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 # 27

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 # 28

The concept of direction and position are purely

absolute A
relative B
absolute or relative C
none of these D

Question # 29

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 # 30

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

Sr.#	Question	Answer
1	Photoelectrons are emitted when ultraviolet light falls on:	A. Casium B. Silver C. Potassium D. Any of these
2	According to the electromagnetic wave theory of light, increasing the intensity of incident light should increase the	A. number of photoelectrons B. size of the photoelectrons C. charge on photoelectrons D. K.E of photoelectrons
3	According to the special theory of relativity, time is	A. absolute quantity B. not absolute quantity C. constant quantity D. none of these
4	When platinum wire is heated, then at the temperature of 500 ^oC, it becomes:	A. Yellow B. Orange red C. Dull red D. White
5	Converse of pair production is known as	A. Compton effect B. annihilation of matter C. photoelectric effect D. none of these
6	Compton shift refers to:	A. Photon B. Meson C. Proton D. Positron
7	The idea of quantization of energy was proposed by:	A. Einstein B. Max.Planck C. Maxwell D. Bohr
8	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
9	A high temperature, the proportion of shorter wavelengths radiation, emitted by the body	A. decreases B. first increases then decreases C. increases D. any one of them
10	When platinum wire is heated, it appears cherry red at	A. 1600°C B. 900°C C. 1100°C D. 1300°C

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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

The threshold frequency of sodium is 6 x 106MHz. The cut-off wavelength for this metal will be