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ECAT Pre General Science Physics Chapter 19 Dawn of Modern Physics Online Test MCQs With Answers
Question # 1
The photoelectric effect, the maximum energy of photoelectrons depends on the
Choose an answer
particular metal surface
frequency of incident light
both of them
none of them
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Question # 2
The energy of a photon is represented by
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h/c
2
h/T
hc
2
hf/c
2
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Question # 3
The emission of electrons from a metal surface when exposed to light of suitable frequency is called the
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pair production
Compton effect
photoelectric effect
relativity
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Question # 4
When a platinum wire is heated, it appears yellow at
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1600°C
900°C
1100°C
1300°C
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Question # 5
A black body is
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an ideal absorber
an ideal radiator
both of them
none of them
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Question # 6
As the light shines on the metal surface, the electrons are ejected
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slowly
instantaneously
either of these
none of these
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Question # 7
A photon is considered to have
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Momentum
Energy
Wavelength
All of the above
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Question # 8
The energy of a photon in a beam of infrared radiation of wavelength 1240 nm is
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100 ev
10
6
e v
10
3
e v
1.0 e v
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Question # 9
The energy of photon 'E' is proported to
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The magnetic field H
The electric field E
Both the electric and magnetic field H and E
Frequency
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Question # 10
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 # 11
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 # 12
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 # 13
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 # 14
According to the electromagnetic wave theory of light, increasing the intensity of incident light should increase the
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number of photoelectrons
size of the photoelectrons
charge on photoelectrons
K.E of photoelectrons
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Question # 15
The unit of work function is:
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Joule
Electron volt
That of threshold frequency
Both (A) and (B)
None of these
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Question # 16
The special theory of relativity treats problems invoving
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inertial frame of references
accelerating frame of references
both of these
none of these
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Question # 17
Davision and Germer performed experiment to verify
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de-Brogile hypothesis
theory of relativity
Newton's law of gravitation
Mass-energy relation
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Question # 18
Wien's constant is measured in:
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Metre per kelviin
Metre kelvin
Kelvin per meter
Joules
Dynes
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Question # 19
Position and momentum of a particle cannot both be measured simultaneously with perfect accuracy. This is the statement of
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photoelectric effect
pair production
Compton effect
uncertainty principle
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Question # 20
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 # 21
Compton was awarded Nobel prize in physics in
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1921
1923
1925
1927
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Question # 22
The year when A.H. compton was awarded Nobel Prize is:
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1923
1927
1931
1935
None of these
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Question # 23
The location and speed anywhere on earth can now be determined using relativistic effects by NAVISTAR to an accuracy of
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2 cm/s
20 cm/s
200 cm/s
2000 cm/s
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Question # 24
In photoelectric effect the energy of ejected electrons depend on
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The frequency
The intensity
Both frequency and intensity
None of these
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Question # 25
The whole shape of the black body spectrum for all wavelengths was explained by the formula proposed by
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Max plank
Newton
Einstein
J.J. Thomson
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Question # 26
Max Planck received the Nobel Prize for his discovery of energy quants in:
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1718 AD
1918 AH
1818 AD
1918 AD
None of these
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Question # 27
According to the de-Brogile relation, an object of large mass and ordinary speed has
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very small wavelength
very large wavelength
very small frequency
all of these
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Question # 28
When monochromatic light is allowed to fall on cathode, it begins to emit electrons, these electrons are called
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thermoionic electrons
free electrons
photoelectrons
slow electrons
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Question # 29
Momentum is a parameter associated with
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wave motion
particle motion
neither wave nor particle motion
none of these
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Question # 30
The stopping voltage for a certain metal is 100 volts, then the work function for the cathode plate is
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100 J
1.6 x 10
-17
J
100 eV
1.6 x 10
-17
eV
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