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physics MCQs

12th • Chapter 08

50 Questions TextBook
1

A coordinate system in which the law of inertia is valid is called?

A
A non-inertial frame
B
An accelerated frame
C
An inertial frame
D
A rotational frame
2

According to the special theory of relativity, which of the following is a universal constant?

A
The speed of sound
B
The speed of light in free space
C
The acceleration due to gravity
D
The mass of an electron
3

The phenomenon of time slowing down for a moving object as measured by a stationary observer is known as?

A
Length Contraction
B
Time Dilation
C
Mass Variation
D
Time Invariance
4

An object's length appears to be shorter only along the direction of?

A
Its motion
B
Perpendicular to its motion
C
Both parallel and perpendicular to its motion
D
Its acceleration
5

The formula for mass variation with velocity v is?

A
m = m_o * sqrt(1 - v^2/c^2)
B
m = m_o / (1 - v^2/c^2)
C
m = m_o / sqrt(1 - v^2/c^2)
D
m = m_o * (1 - v^2/c^2)
6

The famous mass-energy equivalence equation is?

A
E = mc
B
E = m/c^2
C
E = mc^2
D
E = m^2c
7

A body that has the property to absorb all the radiation entering it is termed as a?

A
Black hole
B
Perfect reflector
C
Black body
D
White body
8

According to Wien's displacement law, as the temperature of a black body increases, the peak wavelength (λ_max) shifts to?

A
Longer wavelengths
B
Shorter wavelengths
C
Remains constant
D
Invisible wavelengths
9

The Stefan-Boltzmann law states that the total energy radiated by a black body is directly proportional to?

A
The square of its Kelvin temperature
B
The cube of its Kelvin temperature
C
The fourth power of its Kelvin temperature
D
Its Kelvin temperature
10

Max Planck proposed that energy is radiated or absorbed in discrete packets called?

A
Electrons
B
Protons
C
Phonons
D
Quanta
11

The energy of a quantum (photon) is given by the formula?

A
E = h/f
B
E = hλ
C
E = fλ
D
E = hf
12

The phenomenon of emission of electrons from a metal surface when exposed to light of suitable frequency is called?

A
Compton effect
B
Pair production
C
Photoelectric effect
D
Annihilation
13

In the photoelectric effect, the minimum energy required for an electron to escape from a metal surface is called?

A
Threshold energy
B
Kinetic energy
C
Photon energy
D
Work function
14

Einstein's photoelectric equation is given by?

A
K.E_max = hf + Φ
B
K.E_max = hf - Φ
C
K.E_max = Φ - hf
D
K.E_max = hf * Φ
15

The minimum frequency of incident light below which no photoelectrons are emitted is called?

A
Critical frequency
B
Resonant frequency
C
Threshold frequency
D
Cut-off frequency
16

A photocell operates on the principle of?

A
Compton effect
B
Pair production
C
Photoelectric effect
D
Wave diffraction
17

The Compton effect describes the scattering of X-rays by?

A
Protons
B
Nuclei
C
Loosely bound electrons
D
Neutrons
18

In the Compton effect, the wavelength of the scattered X-ray is ________ the wavelength of the incident X-ray.

A
Smaller than
B
Equal to
C
Larger than
D
Unrelated to
19

The quantity h/m_o*c is known as?

A
Planck's wavelength
B
de Broglie wavelength
C
Compton wavelength
D
Rydberg wavelength
20

Pair production is the conversion of a high-energy photon into?

A
A proton-neutron pair
B
Two electrons
C
Two positrons
D
An electron-positron pair
21

The minimum energy required for pair production is?

A
0.51 MeV
B
1.02 MeV
C
0.25 MeV
D
2.04 MeV
22

The reverse process of pair production is called?

A
Materialization
B
Compton scattering
C
Annihilation of matter
D
Photoelectric effect
23

Louis de Broglie proposed that particles possess?

A
Only particle-like properties
B
Only wave-like properties
C
Wavelike properties
D
No definite properties
24

The de Broglie wavelength of a particle is given by?

A
λ = h/mv
B
λ = mv/h
C
λ = hf
D
λ = h*mv
25

The Davisson and Germer experiment provided evidence for the wave nature of?

A
Photons
B
Protons
C
Neutrons
D
Electrons
26

Wave-particle duality means that matter and radiation have?

A
Only wave nature
B
Only particle nature
C
Both wave and particle nature
D
Neither wave nor particle nature
27

An electron microscope uses ________ to focus electrons.

A
Optical lenses
B
Mirrors
C
Electric and magnetic fields
D
Diffraction gratings
28

Heisenberg's Uncertainty Principle states that one cannot simultaneously measure with perfect accuracy the ________ of a particle.

A
Position and energy
B
Momentum and time
C
Position and momentum
D
Energy and velocity
29

The uncertainty relation for energy and time is given by?

A
ΔE.Δt ≥ c
B
ΔE.Δt ≥ h
C
ΔE.Δt ≤ h
D
ΔE.Δt ≥ λ
30

A frame of reference that is accelerating is called?

A
An inertial frame
B
A stable frame
C
A non-inertial frame
D
A universal frame
31

The proper time (t_o) is the time interval measured in a frame where the events?

A
Are in motion
B
Are at rest
C
Are accelerating
D
Are observed from a distance
32

As an object's speed v approaches the speed of light c, its mass m approaches?

A
Zero
B
m_o
C
Infinity
D
A constant value
33

The rest mass energy of a particle with rest mass m_o is?

A
E_o = m_o*v^2
B
E_o = m_o*c
C
E_o = 0.5*m_o*c^2
D
E_o = m_o*c^2
34

When a platinum wire is heated to about 1600°C, it appears?

A
Dull red
B
Cherry red
C
Yellow
D
White
35

In the photoelectric effect, increasing the intensity of light increases the?

A
Kinetic energy of photoelectrons
B
Number of photoelectrons
C
Speed of photoelectrons
D
Work function
36

A positron is a particle with the same mass as an electron but with a _______ charge.

A
Negative
B
Neutral
C
Positive
D
Variable
37

In pair annihilation, an electron and a positron destroy each other to produce?

A
One photon
B
Two photons
C
One electron
D
One proton
38

The wavelength of a macroscopic object like a rifle bullet is?

A
Very large and measurable
B
In the X-ray range
C
So small that it is not measurable
D
Equal to the speed of light
39

In the Davisson-Germer experiment, electrons were diffracted by a crystal of?

A
Carbon
B
Nickel
C
Cesium
D
Sodium
40

Niels Bohr's principle of complementarity states that wave and particle aspects of matter?

A
Can be revealed simultaneously
B
Cannot be revealed simultaneously in a single experiment
C
Are not required for a complete description
D
Are identical
41

A photocell made with a cesium coated oxidized silver cathode is designed to respond to?

A
Visible light
B
Ultraviolet radiation
C
X-rays
D
Infrared light
42

Stopping potential is a measure of the?

A
Number of photoelectrons
B
Work function of the metal
C
Maximum kinetic energy of photoelectrons
D
Intensity of incident light
43

In Compton scattering, the change in wavelength (Δλ) is maximum when the scattering angle θ is?

A
0°
B
45°
C
90°
D
180°
44

The concept that matter consists of tiny particles and radiation energy is also granular was first suggested by?

A
Einstein
B
Compton
C
de Broglie
D
Planck
45

The NAVSTAR navigation system relies on the practical application of?

A
Quantum mechanics
B
The theory of relativity
C
The photoelectric effect
D
Newtonian physics
46

For a particle to be confined within a nucleus, its speed would have to be?

A
Less than the speed of light
B
Equal to the speed of light
C
Greater than the speed of light
D
Zero
47

Who received the Nobel Prize in 1921 for his explanation of the photoelectric effect?

A
Max Planck
B
Albert Einstein
C
Niels Bohr
D
Arthur Compton
48

Pair production cannot take place in a vacuum because?

A
Energy is not conserved
B
Charge is not conserved
C
Momentum is not conserved
D
Mass is not conserved
49

Which photon carries the most energy?

A
Red
B
Green
C
Blue
D
Yellow
50

If an electron and a proton have the same de Broglie wavelength, which particle has greater speed?

A
Proton
B
Electron
C
Both have the same speed
D
Cannot be determined