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

Question # 1

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 # 2

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 # 3

When platinum wire is heated, then at the temperature of 500 ^oC, it becomes:

Yellow A
Orange red B
Dull red C
White D
Cherry red E

Question # 4

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 # 5

The inside cavity of the black body is

painted white A
painted silver B
blackened with soot C
painted red D

Question # 6

Compton studied the scattering of x-rays by loosely bound electrons from:

NaCl crystal A
Graphite crystal B
Zirconia C
Copper crystal D
None of these E

Question # 7

When a platinum wire is heated, it appears yellow at

1600°C A
900°C B
1100°C C
1300°C D

Question # 8

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 # 9

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 # 10

The photon of radio-waves has energy of about

1 Me V A
1 Ke v B
10^-10e v C
10¹⁰e v D

Question # 11

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 # 12

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 # 13

An electron is accelerated through a potential difference of 50v. its de-Brogile wavelength is

1.66 x 10^-29m A
1.74 x 10^-10cm B
17.4 x 10^-6m C
1.74 x 10^-10m D

Question # 14

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 # 15

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 # 16

The concept of direction and position are purely

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

Question # 17

The value of the plank's constant 'h' is given by

1.6 x 10^-19J A
1.67 x 10^-27Kg B
6.63 x 10³⁴Js C
6.63 x 10^-34Js D

Question # 18

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 # 19

The special theory of relatively treats the problems involving:

Inertial frames of reference A
Non-inertial frames B
Non-accelerated frame C
Botha (A) and (C) D
Both (B) and (C) E

Question # 20

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 # 21

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 # 22

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 # 23

Converse of pair production is known as

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

Question # 24

From the theory of relativity, momentum p of the photon is related to energy as

p = hfc A
p = hf/c B
p = f(hc,f) C
p = cf/h D

Question # 25

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 # 26

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 # 27

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 # 28

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 # 29

Max plank founded a mathematical model resulting in an equation that describes the shape of observed black body radiation curves exactly, in

1890 A
1895 B
1900 C
1905 D

Question # 30

Wave nature of particle was proposed by

Einstein A
Plank B
De-Brogile C
Max well D

Sr.#	Question	Answer
1	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
2	From the theory of relativity, momentum p of the photon is related to energy as	A. p = hfc B. p = hf/c C. p = f(hc,f) D. p = cf/h
3	When a high energy photon interact with a metal, which of the following effect is most likely to be taken place	A. pair production B. photoelectric effect C. Compton effect D. None of these
4	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)
5	The concept of direction is purely:	A. Absolute B. Relative C. Relative to stars always D. Relative to the sun always
6	When a platinum wire is heated, it appears yellow at	A. 1600°C B. 900°C C. 1100°C D. 1300°C
7	Strictly speaking, the earth is:	A. An accelerated frame of reference B. A non-inertial frame of reference C. An inertial frame of reference D. ^{A non-accelerated frame of reference}
8	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
9	Pair production is the phenomenon in which	A. matter is converted into energy B. energy is converted into matter C. light is converted into electrical energy D. electrical energy is converted into light
10	0.1 kg mass will be equivalent to the energy	A. 9 x 10¹⁵J B. 5 x 10⁸J C. 6 x 10¹⁶J D. 9 x 10^-16J

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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