More Classes
5th Class
6th Class
7th Class
8th Class
9th Class
10th Class
11th Class
12th Class
NAT I
NAT II
CSS
IQ
General Knowledge
MDCAT
ECAT
GAT General
GAT Subject
Other Links
Go to Home
Online Tests
ECAT Pre General Science Physics Chapter 19 Dawn of Modern Physics Online Test MCQs With Answers
Question # 1
According to the electromagnetic wave theory of light, increasing the intensity of incident light should increase the
Choose an answer
number of photoelectrons
size of the photoelectrons
charge on photoelectrons
K.E of photoelectrons
Previous
Skip
Next
Question # 2
The stopping voltage for a certain metal is 100 volts, then the work function for the cathode plate is
Choose an answer
100 J
1.6 x 10
-17
J
100 eV
1.6 x 10
-17
eV
Previous
Skip
Next
Question # 3
The special theory of relativity treats problems invoving
Choose an answer
inertial frame of references
accelerating frame of references
both of these
none of these
Previous
Skip
Next
Question # 4
The year when A.H. compton was awarded Nobel Prize is:
Choose an answer
1923
1927
1931
1935
None of these
Previous
Skip
Next
Question # 5
The energy of a photon in a beam of infrared radiation of wavelength 1240 nm is
Choose an answer
100 ev
10
6
e v
10
3
e v
1.0 e v
Previous
Skip
Next
Question # 6
The whole shape of the black body spectrum for all wavelengths was explained by the formula proposed by
Choose an answer
Max plank
Newton
Einstein
J.J. Thomson
Previous
Skip
Next
Question # 7
Photocell is a device which converts
Choose an answer
chemical energy into electrical energy
electrical energy into light energy
heat energy into electrical energy
light energy into electrical energy
Previous
Skip
Next
Question # 8
According to the de-Brogile relation, an object of large mass and ordinary speed has
Choose an answer
very small wavelength
very large wavelength
very small frequency
all of these
Previous
Skip
Next
Question # 9
Davision and Germer performed experiment to verify
Choose an answer
de-Brogile hypothesis
theory of relativity
Newton's law of gravitation
Mass-energy relation
Previous
Skip
Next
Question # 10
Which of the following phenomenon proves the particle nature of light
Choose an answer
interference
diffraction
photoelectric effect
none of these
Previous
Skip
Next
Question # 11
When platinum wire is heated, it appears cherry red at
Choose an answer
1600
°C
900
°C
1100
°C
1300
°C
Previous
Skip
Next
Question # 12
The value of threshold frequency for different metals is
Choose an answer
different
same
may be different or may be same
none of these
Previous
Skip
Next
Question # 13
Due to relative motion of observer and the frame of reference of events, time always:
Choose an answer
Dilates itself
Contracts itself
Stretches itself
Both (A) and (C)
None of these
Previous
Skip
Next
Question # 14
Max Planck received the Nobel Prize for his discovery of energy quants in:
Choose an answer
1718 AD
1918 AH
1818 AD
1918 AD
None of these
Previous
Skip
Next
Question # 15
The idea of quantization of energy was proposed by:
Choose an answer
Einstein
Max.Planck
Maxwell
Bohr
Rutherford
Previous
Skip
Next
Question # 16
According to the special theory of relativity, time is
Choose an answer
absolute quantity
not absolute quantity
constant quantity
none of these
Previous
Skip
Next
Question # 17
the symbol to be used in relativity problems denotes:
Choose an answer
Dilated time
Proper time
Life time
Half time
None of these
Previous
Skip
Next
Question # 18
A high temperature, the proportion of shorter wavelengths radiation, emitted by the body
Choose an answer
decreases
first increases then decreases
increases
any one of them
Previous
Skip
Next
Question # 19
In process of annihilation of matter, the two photons produced move in opposite direction to converse
Choose an answer
momentum
charge
energy
mass
Previous
Skip
Next
Question # 20
The special theory of relativity is based on:
Choose an answer
Four postulates
Three postulates
Two postulates
One postulate
None of these
Previous
Skip
Next
Question # 21
The photon of radio-waves has energy of about
Choose an answer
1 Me V
1 Ke v
10
-10
e v
10
10
e v
Previous
Skip
Next
Question # 22
Pair production is the phenomenon in which
Choose an answer
matter is converted into energy
energy is converted into matter
light is converted into electrical energy
electrical energy is converted into light
Previous
Skip
Next
Question # 23
When a platinum wire is heated, it appears orange red at
Choose an answer
500
°C
900
°C
1100
°C
1300
°C
Previous
Skip
Next
Question # 24
the dilation of time applies to the timing processes which are:
Choose an answer
Physical
Chemical
Biological
All of these
None of these
Previous
Skip
Next
Question # 25
The concept of direction is purely:
Choose an answer
Absolute
Relative
Relative to stars always
Relative to the sun always
None of these
Previous
Skip
Next
Question # 26
Photoelectrons are emitted when ultraviolet light falls on:
Choose an answer
Casium
Silver
Potassium
Any of these
None of these
Previous
Skip
Next
Question # 27
The mass 'm' of a body moving at 0.8 c (whose rest mass is mo) becomes
Choose an answer
2 mo
1.67 mo
0.67 mo
2.67 mo
Previous
Skip
Next
Question # 28
The ratio of energy E to the corresponding frequency (f) of the radiation (emitted or absorbed) is called:
Choose an answer
Wien's constant
Stefen's constnat
Planck's constant
Boltzmann's constant
None of these
Previous
Skip
Next
Question # 29
The unit of work function is:
Choose an answer
Joule
Electron volt
That of threshold frequency
Both (A) and (B)
None of these
Previous
Skip
Next
Question # 30
Wave nature of particle was proposed by
Choose an answer
Einstein
Plank
De-Brogile
Max well
Previous
Skip
Next
Question # 31
An electron is accelerated through a potential difference of 50v. its de-Brogile wavelength is
Choose an answer
1.66 x 10
-29
m
1.74 x 10
-10
cm
17.4 x 10
-6
m
1.74 x 10
-10
m
Previous
Skip
Next
Question # 32
According to the special theory of relativity
Choose an answer
mass and energy are same entities
mass and energy are same entities but interconverible
mass and energy are different entities but interconverible
mass and energy are different entities but non-interconveritble
Previous
Skip
Next
Question # 33
There is no way to detect:
Choose an answer
Absolute uniform motion
Accelerated motion
State rest
State of motion
None of these
Previous
Skip
Next
Question # 34
The value of the plank's constant 'h' is given by
Choose an answer
1.6 x 10
-19
J
1.67 x 10
-27
Kg
6.63 x 10
34
Js
6.63 x 10
-34
Js
Previous
Skip
Next
Back