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
Albert Einstein got the Nobel prize in physics for his explanation of photoelectric effect in
Choose an answer
1916
1919
1921
1923
Previous
Skip
Next
Question # 2
When a position comes close to an electron they annihilate into
Choose an answer
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
Previous
Skip
Next
Question # 3
Compton studied the scattering of x-rays by loosely bound electrons from:
Choose an answer
NaCl crystal
Graphite crystal
Zirconia
Copper crystal
None of these
Previous
Skip
Next
Question # 4
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 # 5
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 # 6
A black body is
Choose an answer
an ideal absorber
an ideal radiator
both of them
none of them
Previous
Skip
Next
Question # 7
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 # 8
When platinum wire is heated, then at the temperature of 500
o
C, it becomes:
Choose an answer
Yellow
Orange red
Dull red
White
Cherry red
Previous
Skip
Next
Question # 9
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 # 10
Photoelectrons are emitted when ultraviolet light falls on:
Choose an answer
Casium
Silver
Potassium
Any of these
None of these
Previous
Skip
Next
Question # 11
If a body reaches a speed equal to the speed of light, then its mass will became
Choose an answer
zero
very small
infinity
none of these
Previous
Skip
Next
Question # 12
From the theory of relativity, momentum p of the photon is related to energy as
Choose an answer
p = hfc
p = hf/c
p = f(hc,f)
p = cf/h
Previous
Skip
Next
Question # 13
In order to produce pair production, a photon must have a energy
Choose an answer
0.511 Me v
0.256 Me v
1.02 Me v
0.956 Me v
Previous
Skip
Next
Question # 14
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 # 15
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
Previous
Skip
Next
Question # 16
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 # 17
Which one of the following physical quantities changes with relativistic speed
Choose an answer
Length
Mass
Time
All of the above
Previous
Skip
Next
Question # 18
The special theory of relativity is based on the
Choose an answer
one postulate
two postulates
three postulates
four postulates
Previous
Skip
Next
Question # 19
There is certain frequency below which no electrons are emitted from the metal surface, this frequency is known as
Choose an answer
maximum frequency
minimum frequency
threshold frequency
all of these
Previous
Skip
Next
Question # 20
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 # 21
If you are moving at relativistic speed between two points that are a fixed distance apart, then the distance between the two points appers
Choose an answer
larger
shorter
equal
none of these
Previous
Skip
Next
Question # 22
The threshold frequency of sodium is 6 x 10
6
MHz. The cut-off wavelength for this metal will be
Choose an answer
500 m
500 nm
500 km
500 cm
None of these
Previous
Skip
Next
Question # 23
The Nobel Prize on the explanation of photoelectric effect was awarded to:
Choose an answer
Max. Planck
Maxwell
Bohr
Rutherford
None of these
Previous
Skip
Next
Question # 24
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 # 25
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 # 26
A non-inertial frame of reference is one, in which
Choose an answer
law of inertial is valid
all laws of physics are the same in all frames
a>0 or a<0
a=0
Previous
Skip
Next
Question # 27
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 # 28
Converse of pair production is known as
Choose an answer
Compton effect
annihilation of matter
photoelectric effect
none of these
Previous
Skip
Next
Question # 29
Victor de-Brogile received the Nobel prize in physics in
Choose an answer
1925
1929
1932
1935
Previous
Skip
Next
Question # 30
A particle having mass and charge equal to that of an electron is called:
Choose an answer
Proton
Positron
Pion
Pi-meson
Both (C) and (D)
Previous
Skip
Next
Question # 31
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
Back