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

The length contraction happens only

Question # 2

When monochromatic light is allowed to fall on cathode, it begins to emit electrons, these electrons are called

Question # 3

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

Question # 4

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

Question # 5

Photoelectrons are emitted when ultraviolet light falls on:

Question # 6

A particle having mass and charge equal to that of an electron is called:

Question # 7

Photocell is a device which converts

Question # 8

When a position comes close to an electron they annihilate into

Question # 9

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

Question # 10

Practically the quantity v/c is always:

Question # 11

Max Planck received the Nobel Prize for his discovery of energy quants in:

Question # 12

According to the special theory of relativity, time is

Question # 13

The positron was discovered by:

Question # 14

The energy of the 4th orbit in hydrogen atom is

Question # 15

Newton's law of motion do not hold in

Question # 16

the dilation of time applies to the timing processes which are:

Question # 17

Position was discovered by Carl Anderson in

Question # 18

The special theory of relativity treats problems invoving

Question # 19

The existence of position was predicted by Dirace in

Question # 20

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

Question # 21

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

Question # 22

The Einstein's changes in length, mass and time are not observed in common life because

Question # 23

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

Question # 24

the symbol to be used in relativity problems denotes:

Question # 25

The value of the Stephen's constant for black body radiations is given by

Question # 26

The concept of direction and position are purely

Question # 27

Due to relative motion of observer and the frame of reference of events, time always:

Question # 28

The mass 'm' of a body moving at 0.8 c (whose rest mass is mo) becomes

Question # 29

Electromagnetic radiation or photons interact with matter in

Question # 30

In photoelectric effect the energy of ejected electrons depend on

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ECAT Physics Chapter 19 Important MCQ's

Sr.# Question Answer
1 The ratio of energy E to the corresponding frequency (f) of the radiation (emitted or absorbed) is called:
A. Wien's constant
B. Stefen's constnat
C. Planck's constant
D. Boltzmann's constant
2 The intensity of emitted energy (with wavelength) radiated from a black body at different temperatures was initially measured by:
A. Lummer
B. Planck
C. Pringsheim
D. Both (A ) and (B)
3 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
4 Momentum is a parameter associated with
A. wave motion
B. particle motion
C. neither wave nor particle motion
D. none of these
5 In order to produce pair production, a photon must have a energy
A. 0.511 Me v
B. 0.256 Me v
C. 1.02 Me v
D. 0.956 Me v
6 The Einstein's changes in length, mass and time are not observed in common life because
A. We dont observer then seriously
B. The masses are too large
C. Their speed is too small than the speed of right
D. All of the above
7 The special theory of relativity is based on:
A. Four postulates
B. Three postulates
C. Two postulates
D. One postulate
8 The existence of position was predicted by Dirace in
A. 1920
B. 1925
C. 1930
D. 1928
9 When platinum wire is heated, it appears cherry red at
A. 1600°C
B. 900°C
C. 1100°C
D. 1300°C
10 Max Planck received the Nobel Prize for his discovery of energy quants in:
A. 1718 AD
B. 1918 AH
C. 1818 AD
D. 1918 AD

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