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Physics for IGCSE & O level - Atoms And Radioactivity (Section 1)

1
What element is commonly used in a nuclear fusion reactor?
Answer
(C)
Hydrogen
2
What type of radiation is an electromagnetic wave?
Answer
(C)
Gamma
3
Which of the following statements correctly describes what happens to the atomic mass and atomic number during gamma decay?
Answer
(B)
Atomic mass remains the same, and the atomic number remains the same.
4
What is the charge of a beta particle?
Answer
(B)
-1
5
Which of these are emitted during radioactive decay?
Answer
A
B
C
6
Why are some isotopes more stable than others?
Answer
(C)
Due to an ideal ratio of neutrons to protons
7
What type of decay results in an increase of the atomic number by one?
Answer
(B)
Beta-minus decay
8
What type of radioactive decay leads to the emission of a particle with the same mass as an electron but with a positive charge?
Answer
(C)
Beta-plus decay
9
What does the term 'half-life' refer to?
Answer
(A)
The time it takes for half of the atoms in a sample to decay.
10
What is a fundamental particle?
Answer
(B)
A particle that is not made up of other particles.
11
Which of the following is an example of an unstable isotope?
Answer
(B)
Uranium-238
12
What happens to the mass number during beta decay?
Answer
(C)
Remains the same
13
What is the name of the process when a neutron is absorbed by a nucleus?
Answer
(D)
Nuclear reaction
14
What is the approximate half-life of the radioactive isotope used in the example of the graph?
Answer
(B)
10 days
15
What does the decay rate of a radioactive substance depend on?
Answer
(D)
The substance's half-life
16
Which types of radiation can be deflected by a magnetic field?
Answer
A
B
17
Which of the following is a potential source of background radiation?
Answer
(D)
All of the above
18
What is the purpose of the symbol of the alpha particle in a nuclear equation?
Answer
(C)
To represent a helium nucleus
19
What is the approximate composition of an alpha particle?
Answer
(B)
Two protons and two neutrons
20
What type of radiation is the least penetrating?
Answer
(A)
Alpha
21
What is an example of a natural source of background radiation?
Answer
(C)
Cosmic rays
22
In which form is the amount of background radiation in the environment?
Answer
(B)
Very small amounts.
23
Which type of decay emits an alpha particle?
Answer
(B)
Alpha decay
24
What is the key difference between Thomson's and Rutherford's atomic models?
Answer
(B)
The distribution of positive charge
25
If the half-life of a radioactive substance is 10 years, what fraction of the original substance will remain after 20 years?
Answer
(B)
1/4
26
What is a chain reaction in nuclear fission?
Answer
(C)
A self-sustaining reaction where neutrons cause further fission.
27
Which is a unit of radiation exposure?
Answer
(C)
Gray
28
According to Rutherford's model, what is mostly empty?
Answer
(B)
The atom
29
Which of the following is a type of nuclear radiation?
Answer
(B)
Alpha
30
What is the main source of background radiation in many areas?
Answer
(D)
The ground
31
What is the source of energy in a nuclear power station?
Answer
(A)
Fission
32
What type of emission does not change the mass number of a nucleus?
Answer
(C)
Gamma
33
During beta-plus decay, what happens to a proton within the nucleus?
Answer
(A)
It transforms into a neutron and emits a positron.
34
What is the composition of an alpha particle?
Answer
(C)
Two protons and two neutrons
35
Which of the following statements about isotopes is true?
Answer
(A)
Isotopes have the same number of protons but a different number of neutrons.
36
Which type of radiation can penetrate the deepest?
Answer
(C)
Gamma
37
What happens to the atomic number and the mass number during Beta-minus decay?
Answer
(A)
Atomic number increases by 1; Mass number remains the same
38
What type of particle is emitted from the nucleus during beta minus decay?
Answer
(B)
Beta particle (electron)
39
What type of radiation is stopped by a few millimeters of aluminum?
Answer
(B)
Beta particles
40
In the context of radioactivity, what does 'activity' measure?
Answer
(B)
The rate at which a radioactive source emits radiation.
41
What is the term for the spontaneous disintegration of a nucleus?
Answer
(C)
Radioactive decay
42
Which type of radiation is most easily stopped by a sheet of paper?
Answer
(A)
Alpha particles
43
What is the main purpose of the coolant in a nuclear reactor?
Answer
(C)
To remove heat
44
What particles are found in the nucleus?
Answer
A
B
45
What happens to the nucleus of an atom during gamma decay?
Answer
(C)
The nucleus emits a high-energy photon.
46
What is the role of control rods in a nuclear reactor?
Answer
(B)
To absorb neutrons to control the rate of reaction.
47
What does a Geiger-Müller tube measure?
Answer
(B)
The number of ionizing particles
48
What is the role of a moderator in a nuclear reactor?
Answer
(B)
To slow down neutrons
49
Which type of radiation is least likely to penetrate human skin?
Answer
(A)
Alpha
50
How can exposure to radiation be minimized?
Answer
B
C