Radioactivity: Types, Decay, Reactions, and Applications

Question 1

The half-life of a radioactive substance represents the time it takes for:

Accepted Answer

Half of the sample to decay

Answer

All of the sample to decay

Answer

One-quarter of the sample to decay

Answer

Double the sample to decay

Question 2

In a nuclear reactor, the purpose of the moderator is to:

Accepted Answer

Slow down neutrons

Answer

Speed up neutrons

Answer

Capture neutrons

Answer

Emit neutrons

Question 3

Which of the following is a characteristic of gamma radiation?

Accepted Answer

High energy and no charge

Answer

Low energy and high charge

Answer

High charge and low energy

Answer

No energy and high charge

Question 4

The SI unit of activity in radioactivity is the:

Accepted Answer

Becquerel (Bq)

Answer

Gray (Gy)

Answer

Sievert (Sv)

Answer

Coulomb (C)

Question 5

Which of the following isotopes is naturally radioactive?

Accepted Answer

Uranium-238

Answer

Cobalt-60

Answer

Technetium-99m

Answer

Cesium-137

Question 6

The primary reason for using lead as a shielding material for radioactive sources is to:

Accepted Answer

Absorb gamma radiation

Answer

Reflect neutron radiation

Answer

Capture alpha particles

Answer

Emit beta particles

Question 7

The ethical consideration of paramount importance in the use of nuclear technology is:

Accepted Answer

Safety and environmental impact

Answer

Economic benefits

Answer

Political implications

Answer

Social responsibility

Question 8

Which of the following is NOT a type of radioactive decay?

Accepted Answer

Neutron emission

Answer

Alpha decay

Answer

Beta decay

Answer

Gamma decay

Question 9

Which process is used to generate energy in nuclear power plants?

Accepted Answer

Nuclear fission

Answer

Nuclear fusion

Answer

Radioactive decay

Answer

Nuclear transmutation

Question 10

The half-life of a radioactive isotope is the amount of time it takes for what percentage of the initial number of atoms to decay?

Accepted Answer

50%

Answer

25%

Answer

75%

Answer

100%

Question 11

In the context of nuclear power plants, what is the main purpose of bombarding uranium atoms with neutrons?

Accepted Answer

To initiate nuclear fission and release energy

Answer

To produce radioactive isotopes for industrial use

Answer

To stabilize uranium and prevent decay

Answer

To detect the presence of impurities in the uranium

Question 12

Which of the following materials is most effective in shielding against radiation?

Accepted Answer

Lead

Answer

Concrete

Answer

Plastic

Answer

Water

Question 13

When working with radioactive isotopes, what should be the primary concern regarding safety?

Accepted Answer

Potential for radiation exposure and its biological effects

Answer

Cost of acquisition and disposal of the isotopes

Answer

Difficulty in handling and storing the isotopes

Answer

Limited availability of certain isotopes

Question 14

What is a characteristic property of beta particles?

Accepted Answer

Negatively charged and composed of electrons

Answer

High energy and penetrating power

Answer

Low energy and high ionizing ability

Answer

Positively charged and composed of protons

Question 15

Which of the following factors has no influence on the rate of radioactive decay?

Accepted Answer

Magnetic field

Answer

Isotope type

Answer

Temperature

Answer

Chemical environment

Question 16

Which unit is used to express the activity of a radioactive source?

Accepted Answer

Becquerel

Answer

Gray

Answer

Sievert

Answer

Curie

Question 17

What is radiation dose and why is it crucial for radiation safety?

Accepted Answer

Energy absorbed per unit mass of irradiated material

Answer

Number of radioactive particles emitted per unit time

Answer

Type of radiation released (alpha, beta, or gamma)

Answer

Distance between radiation source and irradiated object

Question 18

The half-life of a radioactive substance is the time it takes for:

Accepted Answer

Half of the substance to decay

Answer

All of the substance to decay

Answer

Double the amount of substance to decay

Answer

The decay rate to double

Question 19

Which of the following is a naturally occurring radioactive element?

Accepted Answer

Uranium

Answer

Cobalt-60

Answer

Cesium-137

Answer

Plutonium-239

Question 20

The SI unit used to measure the activity of radioactive sources is:

Accepted Answer

Becquerel

Answer

Curie

Answer

Gray

Answer

Sievert

Question 21

Nuclear fission involves the:

Accepted Answer

Splitting of a heavy nucleus into two lighter nuclei

Answer

Combining of two lighter nuclei into a heavier nucleus

Answer

Addition of neutrons to a nucleus

Answer

Removal of protons from a nucleus

Question 22

Which of the following factors does NOT affect the rate of radioactive decay?

Accepted Answer

Presence of a catalyst

Answer

Temperature

Answer

Concentration of the radioactive substance

Answer

Nature of the radioactive isotope

Question 23

Which of the following is not a type of radioactive decay?

Accepted Answer

Neutron emission

Answer

Alpha decay

Answer

Beta decay

Answer

Gamma decay

Question 24

The half-life of a radioactive substance is the time taken for:

Accepted Answer

The number of atoms to reduce to one-half of its initial value

Answer

The activity to reduce to one-quarter of its initial value

Answer

The mass to reduce to one-half of its initial value

Answer

The energy released to reduce to one-half of its initial value

Question 25

What is the SI unit for radioactivity?

Accepted Answer

Becquerel

Answer

Gray

Answer

Sievert

Answer

Coulomb

Question 26

Who is credited with the discovery of radioactivity?

Accepted Answer

Marie Curie

Answer

Albert Einstein

Answer

Isaac Newton

Answer

Ernest Rutherford

Question 27

Which type of radiation has the highest penetrating power?

Accepted Answer

Gamma

Answer

Alpha

Answer

Beta

Answer

X-rays

Question 28

What is the primary purpose of a Geiger-Müller counter?

Accepted Answer

To detect the presence of radioactive substances

Answer

To measure the intensity of radiation

Answer

To shield against radiation

Answer

To treat cancer

Question 29

Which particle emitted during radioactive decay has the greatest penetrating power?

Accepted Answer

Gamma ray

Answer

Alpha particle

Answer

Beta particle

Answer

Neutron

Question 30

What is the process by which a stable nucleus captures a neutron and transforms into an unstable isotope?

Accepted Answer

Neutron activation

Answer

Radioactive decay

Answer

Nuclear fusion

Answer

Nuclear fission

Question 31

Which type of radiation requires the most shielding?

Accepted Answer

Gamma rays

Answer

Alpha particles

Answer

Beta particles

Answer

Neutrons

Question 32

What is the term for the spontaneous emission of radiation from an unstable nucleus?

Accepted Answer

Radioactive decay

Answer

Nuclear fission

Answer

Nuclear fusion

Answer

Chain reaction

Question 33

What is the SI unit of radioactivity?

Accepted Answer

Becquerel

Answer

Gray

Answer

Sievert

Answer

Rad

Question 34

What is the primary mechanism behind the operation of a Geiger counter?

Accepted Answer

Detection of charged particles

Answer

Measurement of absorbed dose

Answer

Identification of radioactive isotopes

Answer

Monitoring of radiation exposure

Question 35

Radioactivity has significant societal implications. Discuss both its potential benefits and associated risks, providing specific examples of each.

Accepted Answer

Radioactivity has both potential benefits and risks, requiring careful consideration for its societal implications.

Answer

Radioactivity has no societal implications.

Answer

Radioactivity offers only benefits, with no associated risks.

Answer

Radioactivity has solely negative societal implications.

Question 36

Which of the following is **not** a type of radioactive decay?

Accepted Answer

Nuclear fusion

Answer

Beta decay

Answer

Gamma decay

Answer

Alpha decay

Question 37

The half-life of a radioactive isotope is the time it takes for:

Accepted Answer

Half of the radioactive nuclei to decay

Answer

A quarter of the nuclei to decay

Answer

None of the nuclei to decay

Answer

All of the nuclei to decay

Question 38

Which of the following is a medical application of radioactivity?

Accepted Answer

Cancer treatment (radiotherapy)

Answer

Space exploration

Answer

Nuclear weapons

Answer

Power generation

Question 39

In a nuclear reaction, the total:

Accepted Answer

Mass-energy is conserved

Answer

Energy is conserved

Answer

Charge is conserved

Question 40

Which of the following is a unit of radioactivity?

Accepted Answer

Becquerel (Bq)

Answer

Ampere

Answer

Newton

Answer

Joule

Question 41

Alpha particles are:

Accepted Answer

Helium nuclei (2 protons and 2 neutrons)

Answer

Electrons

Answer

Protons

Answer

Neutrons

Question 42

Gamma rays are:

Accepted Answer

High-energy photons with no mass or charge

Answer

Subatomic particles

Answer

Neutrinos

Answer

Charged particles

Question 43

Which of the following is an effective shielding material for radioactivity?

Accepted Answer

Lead

Answer

Plastic

Answer

Paper

Answer

Wood

Question 44

Which of the following is a major concern associated with nuclear waste disposal?

Accepted Answer

Long-term radioactivity and potential environmental contamination

Answer

Noise pollution

Answer

Air pollution

Answer

Water contamination