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ECAT Physics Chapter 19 Dawn of Modern Physics Online Test MCQs With Answers
Question # 1
Photoelectrons are emitted when ultraviolet light falls on:
Choose an answer
Casium
Silver
Potassium
Any of these
None of these
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Question # 2
According to Einstein, with the great increase in the speed of the body, the relativistic mass of the body
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Remains constant
Decreases
Increases to infinity
Reduced to zero
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Question # 3
A photon is considered to have
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Momentum
Energy
Wavelength
All of the above
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Question # 4
The analysis of the distribution of wavelengths of the radiation emitted from a hot body set the foundation of new mechanics, known as
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classical mechanics
Newtonian mechanics
quantum mechanics
statistical mechanics
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Question # 5
When the atomic particle are moving with velocities approaching that of light:
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Newton's laws become valid
Relativistic effects become prominent
Botha(A) and (B) are valid
Neither (A)nor (B)
There mass becomes zero.
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Question # 6
In order to produce pair production, a photon must have a energy
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0.511 Me v
0.256 Me v
1.02 Me v
0.956 Me v
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Question # 7
Absolute motion cannot be detected
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in its own frame of references
in a different frame of references
both in its frame and different frame of references
none of these
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Question # 8
The length contraction happens only
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Opposite to the direction of motion
along the direction of motion
perpendicular to the direction of motion
In any direction
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Question # 9
Wave nature of particle was proposed by
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Einstein
Plank
De-Brogile
Max well
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Question # 10
A particle having mass and charge equal to that of an electron is called:
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Proton
Positron
Pion
Pi-meson
Both (C) and (D)
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Question # 11
Intensity of light determines the:
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Energy of each photon
Number of photons
Speed of photons
Size of photons
None of these
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Question # 12
Which of the following phenomenon proves the particle nature of light
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interference
diffraction
photoelectric effect
none of these
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Question # 13
According to the special theory of relativity, a moving clock
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runs faster
runs slower
neither runs faster nor slower
all of these
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Question # 14
If A represents linear momentum and c, the velocity of light, then unit of pc in international system of units is:
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Newton
Joule
Joule-Sec
Joule-s
-1
Watt
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Question # 15
According to Einstein, with the great increase in the speed of the body the relativistic length of the body
Choose an answer
Remains constant
Decreases
Increases
Reduces to zero
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Question # 16
Max plank received the Nobel Prize in physics for his discovery of energy quanta in
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1900
1906
1912
1918
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