physics MCQs

1

Who discovered the neutron in 1932?

A

Ernest Rutherford

B

Marie Curie

C

James Chadwick

D

J.J. Thomson

2

The number of protons inside a nucleus is called the:

A

Mass number

B

Nucleon number

C

Neutron number

D

Atomic number

3

Isotopes of an element have the same number of but a different number of .

A

neutrons, protons

B

protons, neutrons

C

electrons, protons

D

neutrons, electrons

4

The third isotope of hydrogen, which has one proton and two neutrons, is called:

A

Protium

B

Deuterium

C

Tritium

D

Helium

5

A device used to separate isotopes and measure their masses accurately is called a:

A

Geiger counter

B

Wilson cloud chamber

C

Mass spectrograph

D

Solid-state detector

6

In a mass spectrograph, the mass of an ion is proportional to:

A

B

V

C

B²

D

r

7

The mass of a nucleus is always ______ the total mass of its constituent protons and neutrons.

A

equal to

B

greater than

C

less than

D

twice

8

The energy equivalent of the mass defect is known as:

A

Kinetic energy

B

Potential energy

C

Rest mass energy

D

Binding energy

9

According to the binding energy per nucleon curve, which element is the most stable?

A

Uranium

B

Helium

C

Iron

D

Hydrogen

10

Radioactivity was discovered by:

A

Marie Curie

B

Pierre Curie

C

Henri Becquerel

D

Rutherford

11

Elements with a charge number Z greater than ______ are generally unstable and radioactive.

A

58

B

82

C

92

D

100

12

Which type of radiation is composed of helium nuclei?

A

Alpha (α) particles

B

Beta (β) particles

C

Gamma (γ) rays

D

X-rays

13

Which radiation bends towards the positive plate in an electric field?

A

Alpha (α) particles

B

Beta (β) particles

C

Gamma (γ) rays

D

Neutrons

14

When a nucleus emits an alpha particle, its mass number A decreases by:

A

1

B

2

C

4

D

0

15

When a nucleus emits a beta particle, its charge number Z:

A

increases by 1

B

decreases by 1

C

remains the same

D

decreases by 2

16

The half-life of a radioactive element is the time in which:

A

all of its atoms decay

B

half of its atoms decay

C

one-fourth of its atoms decay

D

it becomes stable

17

The relationship between decay constant (λ) and half-life (T₁/₂) is:

A

λT₁/₂ = 1

B

λ = 0.693 / T₁/₂

C

T₁/₂ = 0.693 / λ

D

Both B and C

18

Which particle produces the most intense ionization along its path?

A

Alpha (α) particle

B

Beta (β) particle

C

Gamma (γ) ray

D

Neutron

19

The path of which particle in a Wilson cloud chamber is described as thick, straight, and continuous?

A

Beta (β) particle

B

Gamma (γ) ray

C

Alpha (α) particle

D

Neutron

20

The 'dead time' of a Geiger-Muller counter refers to the time during which:

A

it is warming up

B

the power is off

C

it cannot detect further particles

D

it counts accurately

21

A solid-state detector is essentially a specially designed:

A

Capacitor

B

Resistor

C

Inductor

D

p-n junction

22

In Rutherford's nuclear reaction experiment in 1918, he bombarded nitrogen with alpha particles to produce:

A

Carbon and a proton

B

Oxygen and a proton

C

Neon and a neutron

D

Oxygen and a neutron

23

The reaction in which a heavy nucleus splits into two smaller nuclei is called:

A

Nuclear fusion

B

Nuclear fission

C

Alpha decay

D

Beta decay

24

The fission of a Uranium-235 nucleus by a slow neutron releases approximately how much energy?

A

20 MeV

B

200 MeV

C

2 MeV

D

2 GeV

25

In a controlled chain reaction, how many neutrons from each fission event cause another fission?

A

All of them

B

Two

C

Three

D

One on average

26

The mass of uranium required to sustain a fission chain reaction is called:

A

Safe mass

B

Subcritical mass

C

Supercritical mass

D

Critical mass

27

Which material is commonly used for control rods in a nuclear reactor?

A

Graphite

B

Heavy water

C

Cadmium

D

Uranium

28

The function of a moderator in a nuclear reactor is to:

A

absorb neutrons

B

speed up neutrons

C

slow down neutrons

D

cool the core

29

The reaction where two light nuclei merge to form a heavier nucleus is called:

A

Nuclear fission

B

Nuclear fusion

C

Photoelectric effect

D

Compton scattering

30

Nuclear fusion reactions in the Sun are also known as:

A

Fission reactions

B

p-p reactions

C

chain reactions

D

combustion

31

Radiation that is always present in our environment is called:

A

Artificial radiation

B

Medical radiation

C

Background radiation

D

Industrial radiation

32

The SI unit for the absorbed dose of radiation is the:

A

Sievert (Sv)

B

Becquerel (Bq)

C

Gray (Gy)

D

Curie (Ci)

33

The quantity that accounts for the differing biological effects of various types of radiation is the:

A

Absorbed dose

B

Activity

C

Equivalent dose

D

Half-life

34

A radioactive isotope used to follow a chemical or biological process is called a:

A

Moderator

B

Tracer

C

Detector

D

Controller

35

Radiotherapy with gamma rays from which isotope is often used to treat cancer?

A

Cobalt-60

B

Iodine-131

C

Carbon-14

D

Uranium-235

36

Which of the four fundamental forces confines neutrons and protons within the nucleus?

A

Gravitational force

B

Electromagnetic force

C

Weak nuclear force

D

Strong nuclear force

37

Particles that experience the strong nuclear force are called:

A

Leptons

B

Photons

C

Hadrons

D

Electrons

38

Which of the following is a lepton?

A

Proton

B

Neutron

C

Electron

D

Meson

39

According to the quark model, a proton is composed of:

A

three down quarks

B

two up quarks and one down quark

C

one up quark and two down quarks

D

two down quarks and one up quark

40

According to the quark model, a neutron is composed of:

A

three up quarks

B

two up quarks and one down quark

C

one up quark and two down quarks

D

a quark and an antiquark

41

The charge of an 'up' quark is:

A

+2/3 e

B

-1/3 e

C

+1 e

D

-1 e

42

The charge of a 'down' quark is:

A

+2/3 e

B

-1/3 e

C

+1 e

D

0

43

In the process of pair production, a gamma-ray photon must have a minimum energy of:

A

0.51 MeV

B

1.02 MeV

C

931 MeV

D

200 MeV

44

In a Wilson cloud chamber, beta particles form which kind of tracks?

A

Thick and straight

B

Thin and discontinuous

C

No definite tracks

D

Short and dense

45

What is the main purpose of a 'quenching gas' in a G-M tube?

A

To increase ionization

B

To prevent spurious counts

C

To amplify the pulse

D

To cool the tube

46

Heavy water is used in some nuclear reactors as a:

A

Fuel

B

Control rod

C

Coolant

D

Moderator

47

In the sun, the p-p reaction cycle ultimately fuses four protons into one:

A

Deuteron nucleus

B

Tritium nucleus

C

Helium nucleus

D

Carbon nucleus

48

A curie (Ci) is a unit of activity equal to how many disintegrations per second?

A

1

B

3.7 x 10¹⁰

C

10⁶

D

6.02 x 10²³

49

The most abundant isotope of naturally occurring neon is:

A

Neon-21

B

Neon-22

C

Neon-20

D

Neon-19

50

The half-life of Radium-226 is approximately:

A

3.8 days

B

23.5 minutes

C

1620 years

D

4.5 x 10⁹ years

Who discovered the neutron in 1932?

The number of protons inside a nucleus is called the:

Isotopes of an element have the same number of ______ but a different number of ______.

The third isotope of hydrogen, which has one proton and two neutrons, is called:

A device used to separate isotopes and measure their masses accurately is called a:

In a mass spectrograph, the mass of an ion is proportional to:

The mass of a nucleus is always ______ the total mass of its constituent protons and neutrons.

The energy equivalent of the mass defect is known as:

According to the binding energy per nucleon curve, which element is the most stable?

Radioactivity was discovered by:

Elements with a charge number Z greater than ______ are generally unstable and radioactive.

Which type of radiation is composed of helium nuclei?

Which radiation bends towards the positive plate in an electric field?

When a nucleus emits an alpha particle, its mass number A decreases by:

When a nucleus emits a beta particle, its charge number Z:

The half-life of a radioactive element is the time in which:

The relationship between decay constant (λ) and half-life (T₁/₂) is:

Which particle produces the most intense ionization along its path?

The path of which particle in a Wilson cloud chamber is described as thick, straight, and continuous?

The 'dead time' of a Geiger-Muller counter refers to the time during which:

A solid-state detector is essentially a specially designed:

In Rutherford's nuclear reaction experiment in 1918, he bombarded nitrogen with alpha particles to produce:

The reaction in which a heavy nucleus splits into two smaller nuclei is called:

The fission of a Uranium-235 nucleus by a slow neutron releases approximately how much energy?

In a controlled chain reaction, how many neutrons from each fission event cause another fission?

The mass of uranium required to sustain a fission chain reaction is called:

Which material is commonly used for control rods in a nuclear reactor?

The function of a moderator in a nuclear reactor is to:

The reaction where two light nuclei merge to form a heavier nucleus is called:

Nuclear fusion reactions in the Sun are also known as:

Radiation that is always present in our environment is called:

The SI unit for the absorbed dose of radiation is the:

The quantity that accounts for the differing biological effects of various types of radiation is the:

A radioactive isotope used to follow a chemical or biological process is called a:

Radiotherapy with gamma rays from which isotope is often used to treat cancer?

Which of the four fundamental forces confines neutrons and protons within the nucleus?

Particles that experience the strong nuclear force are called:

Which of the following is a lepton?

According to the quark model, a proton is composed of:

According to the quark model, a neutron is composed of:

The charge of an 'up' quark is:

The charge of a 'down' quark is:

In the process of pair production, a gamma-ray photon must have a minimum energy of:

In a Wilson cloud chamber, beta particles form which kind of tracks?

What is the main purpose of a 'quenching gas' in a G-M tube?

Heavy water is used in some nuclear reactors as a:

In the sun, the p-p reaction cycle ultimately fuses four protons into one:

A curie (Ci) is a unit of activity equal to how many disintegrations per second?

The most abundant isotope of naturally occurring neon is:

The half-life of Radium-226 is approximately:

Isotopes of an element have the same number of but a different number of .