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Online Tests
ECAT Physics Chapter 19 Dawn of Modern Physics Online Test MCQs With Answers
Question # 1
The energy of the 4th orbit in hydrogen atom is
Choose an answer
2.5 ev
- 3.5 ev
-0.85 ev
-13.6 ev
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Question # 2
The Stephen-Boltzmann law for the black body radiation is given by
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E = T
2
E = -T
2
E = T
4
E = -T
4
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Question # 3
When a platinum wire is heated, it appears dull red at about
Choose an answer
500°C
900°C
1100°C
1300°C
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Question # 4
The threshold frequency of sodium is 6 x 10
6
MHz. The cut-off wavelength for this metal will be
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500 m
500 nm
500 km
500 cm
None of these
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Question # 5
The way through which electromagnetic radiations or photons interact with matter depends upon their:
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Wavelength
Frequency
Energy
Temperature
All of these
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Question # 6
When a position comes close to an electron they annihilate into
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one photon
two photons which travel in the same direction
two photons which travels in the opposite direction
two photons which travel in any direction
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Question # 7
The concept of direction and position are purely
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absolute
relative
absolute or relative
none of these
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Question # 8
The special theory of relatively treats the problems involving:
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Inertial frames of reference
Non-inertial frames
Non-accelerated frame
Botha (A) and (C)
Both (B) and (C)
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Question # 9
de-Broglies hypthesis was experimentally verified by
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Maxwell
Compton
Einstein
Davison and Germer
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Question # 10
Victor de-Brogile received the Nobel prize in physics in
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1925
1929
1932
1935
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Question # 11
The value of threshold frequency for different metals is
Choose an answer
different
same
may be different or may be same
none of these
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Question # 12
The Nobel Prize on the explanation of photoelectric effect was awarded to:
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Max. Planck
Maxwell
Bohr
Rutherford
None of these
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Question # 13
If a material object moves with the speed of light 'C' its mass becomes
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Equal to its rest mass
Four times of its rest mass
Double of its rest mass
Infinite
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Question # 14
Electromagnetic radiation or photons interact with matter in
Choose an answer
two distinct ways
three distinct ways
four distinct ways
five distinct ways
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Question # 15
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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