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

Question # 1

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 # 2

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 # 3

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

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

Question # 4

If A represents linear momentum and c, the velocity of light, then unit of pc in international system of units is:

Newton A
Joule B
Joule-Sec C
Joule-s^-1 D
Watt E

Question # 5

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 # 6

When the atomic particle are moving with velocities approaching that of light:

Newton's laws become valid A
Relativistic effects become prominent B
Botha(A) and (B) are valid C
Neither (A)nor (B) D
There mass becomes zero. E

Question # 7

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 # 8

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 # 9

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 # 10

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 # 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

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 # 13

The idea of quantization of energy was proposed by:

Einstein A
Max.Planck B
Maxwell C
Bohr D
Rutherford E

Question # 14

Momentum is a parameter associated with

wave motion A
particle motion B
neither wave nor particle motion C
none of these D

Question # 15

As compared to the distance measured by an observer on Earth, the distance from Earth to a star measured by an observer in a moving spaceship would seem:

Smaller A
Lerger B
Same C
Much larger D
None of these E

Question # 16

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 # 17

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 # 18

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 # 19

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 # 20

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 # 21

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 # 22

Wien's constant is measured in:

Metre per kelviin A
Metre kelvin B
Kelvin per meter C
Joules D
Dynes E

Question # 23

Max plank received the Nobel Prize in physics for his discovery of energy quanta in

1900 A
1906 B
1912 C
1918 D

Question # 24

Converse of pair production is known as

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

Question # 25

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 # 26

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 # 27

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 # 28

The mass of an object will be doubled at speed

1.6 x 10⁸ms^-1 A
2.6 X 10⁸ms^-1 B
2.6 x 10⁷ms^-1 C
2.6 x 10⁹ms^-1 D

Question # 29

The Stephen-Boltzmann law for the black body radiation is given by

E = T² A
E = -T² B
E = T⁴ C
E = -T⁴ D

Question # 30

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

Sr.#	Question	Answer
1	When the atomic particle are moving with velocities approaching that of light:	A. Newton's laws become valid B. Relativistic effects become prominent C. Botha(A) and (B) are valid D. Neither (A)nor (B)
2	The Stephen-Boltzmann law for the black body radiation is given by	A. E = T² B. E = -T² C. E = T⁴ D. E = -T⁴
3	A non-inertial frame of reference is one, in which	A. law of inertial is valid B. all laws of physics are the same in all frames C. a>0 or a<0 D. a=0
4	Max plank received the Nobel Prize in physics for his discovery of energy quanta in	A. 1900 B. 1906 C. 1912 D. 1918
5	If A represents linear momentum and c, the velocity of light, then unit of pc in international system of units is:	A. Newton B. Joule C. Joule-Sec D. Joule-s^-1
6	The year when A.H. compton was awarded Nobel Prize is:	A. 1923 B. 1927 C. 1931 D. 1935
7	The positron was discovered by:	A. In cosmic radiation B. In 1932 C. By Carl Anderson D. All above
8	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
9	Which of the following phenomenon proves the particle nature of light	A. interference B. diffraction C. photoelectric effect D. none of these
10	The special theory of relativity is based on:	A. Four postulates B. Three postulates C. Two postulates D. One postulate

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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