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

Try The MCQ's Test For ECAT Pre General Science Physics Chapter 19 Dawn of Modern Physics

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ECAT Pre General Science Physics Chapter 19 Dawn of Modern Physics

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Question # 1

Electromagnetic -radiation means:

Question # 2

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

Question # 3

The length contraction happens only

Question # 4

Photoelectric effect takes place with a photon of:

Question # 5

If the radius of first orbit of hydrogen atom is 0.53° A the radius of second orbit will be

Question # 6

Practically the quantity v/c is always:

Question # 7

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

Question # 8

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

Question # 9

A black body is

Question # 10

When a position comes close to an electron they annihilate into

Question # 11

Wien's constant is measured in:

Question # 12

The photon of radio-waves has energy of about

Question # 13

0.1 kg mass will be equivalent to the energy

Question # 14

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

Question # 15

The whole shape of the black body spectrum for all wavelengths was explained by the formula proposed by

Question # 16

Which of the following is not an example of intertial frame

Question # 17

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

Question # 18

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

Question # 19

The mass of an object will be doubled at speed

Question # 20

The inside cavity of the black body is

Question # 21

Absolute motion cannot be detected

Question # 22

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

Question # 23

Converse of pair production is known as

Question # 24

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

Question # 25

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

Question # 26

Intensity of light determines the:

Question # 27

In photoelectric effect the energy of ejected electrons depend on

Question # 28

The location and speed anywhere on earth can now be determined using relativistic effects by NAVISTAR to an accuracy of

Question # 29

There is no way to detect:

Question # 30

The energy of a photon is represented by

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ECAT Physics Chapter 19 Important MCQ's

Sr.# Question Answer
1 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
2 When a platinum wire is heated, it appears white at
A. 1600°C
B. 900°C
C. 1100°C
D. 1300°C
3 The way through which electromagnetic radiations or photons interact with matter depends upon their:
A. Wavelength
B. Frequency
C. Energy
D. Temperature
4 The whole shape of the black body spectrum for all wavelengths was explained by the formula proposed by
A. Max plank
B. Newton
C. Einstein
D. J.J. Thomson
5 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
6 S.I. unit of planks constant is
A. J-s-1
B. J.s
C. J.s-2
D. J.s2
7 Absolute motion cannot be detected
A. in its own frame of references
B. in a different frame of references
C. both in its frame and different frame of references
D. none of these
8 The Stephen-Boltzmann law for the black body radiation is given by
A. E = T2
B. E = -T2
C. E = T4
D. E = -T4
9 The concept of direction and position are purely
A. absolute
B. relative
C. absolute or relative
D. none of these
10 A particle of mass 5.0 mg moves with a speed of 8.0 m/s. Its de-Brogile wavelength is
A. 1.66 m
B. 1.66 x 10-10m
C. 1.66 x 10-29cm
D. 1.66 x 10-29m

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