Questions about Radioactivity
Radioactivity – Multiple Choice Questions
1. What is radioactivity?
A) The emission of sound waves by metals
B) The release of energy from atoms in the form of light
C) The spontaneous emission of particles or rays from unstable atomic nuclei
D) The reaction of elements with oxygen
E) The absorption of energy from external sources
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2. Which of the following particles is NOT emitted during radioactive decay?
A) Alpha particles
B) Beta particles
C) Gamma rays
D) Neutrons
E) Protons in pairs
3. What is an alpha particle composed of?
A) Two neutrons
B) One proton and one electron
C) Two protons and two neutrons
D) Two electrons
E) One neutron and one proton
4. What is the charge of a beta particle?
A) +2
B) -1
C) 0
D) +1
E) -2
5. Gamma radiation differs from alpha and beta radiation in that it:
A) Has a negative charge
B) Is a type of particle
C) Has no mass and no charge
D) Travels slower
E) Is attracted to magnetic fields
6. Which radioactive decay causes the atomic number of the element to increase by 1?
A) Alpha decay
B) Beta-minus decay
C) Gamma decay
D) Beta-plus decay
E) Neutron emission
7. Which of the following is the most penetrating form of radiation?
A) Alpha
B) Beta
C) Gamma
D) Neutron
E) Infrared
8. Which instrument is used to detect radioactivity?
A) Thermometer
B) Spectrophotometer
C) Geiger-Müller counter
D) Bunsen burner
E) Barometer
9. What is meant by “half-life” in radioactivity?
A) The time for all atoms in a sample to decay
B) The time to reduce the volume of the sample by half
C) The time it takes for half the atoms in a sample to decay
D) The time to remove all radiation from a sample
E) The time needed for half the sample to reach boiling point
10. A radioactive isotope has a half-life of 10 years. How much of a 100 g sample remains after 20 years?
A) 10 g
B) 25 g
C) 30 g
D) 40 g
E) 50 g
11. Which of the following isotopes is used in dating ancient fossils?
A) Uranium-238
B) Iodine-131
C) Carbon-14
D) Radium-226
E) Cobalt-60
12. Radioactive decay is an example of what type of reaction?
A) Endothermic
B) Exothermic
C) Reversible
D) Catalytic
E) Neutralization
13. What happens to the atomic number during alpha decay?
A) Increases by 2
B) Decreases by 2
C) Remains the same
D) Increases by 1
E) Decreases by 4
14. The biological damage caused by radiation is mainly due to:
A) Energy released as heat
B) Ionization of molecules in cells
C) Attraction of particles
D) Formation of water molecules
E) Light emission
15. Which particle is deflected the most in a magnetic field?
A) Alpha
B) Beta
C) Gamma
D) Neutron
E) Positron
16. A common medical application of radioactive isotopes is:
A) Treating fungal infections
B) Cleaning surgical tools
C) Diagnosing and treating cancer
D) Measuring heart rate
E) Reducing cholesterol
17. The process of one element changing into another through radioactive decay is called:
A) Radioactive fusion
B) Nuclear splitting
C) Transmutation
D) Fission
E) Transformation
18. Which of the following types of radiation has the least ionizing power?
A) Alpha
B) Beta
C) Gamma
D) Neutron
E) Proton
19. A beta particle is best described as:
A) A high-energy photon
B) A helium nucleus
C) A high-speed electron
D) A positron
E) A neutron
20. Which of these materials can stop gamma radiation effectively?
A) Paper
B) Aluminum foil
C) Cardboard
D) Thick lead or concrete
E) Plastic
- Questions on Radioactive Decay
- Questions about Half-Life
- Questions on Nuclear Fission
- Questions on Nuclear Fusion
Answers and Explanations
1. C – Radioactivity is the spontaneous emission of particles or energy from unstable atomic nuclei.
2. E – Protons in pairs are not typically emitted; alpha, beta, gamma, and neutrons are common.
3. C – An alpha particle is the nucleus of a helium atom: 2 protons and 2 neutrons.
4. B – A beta particle is an electron, which carries a charge of -1.
5. C – Gamma rays have no mass and no charge; they are pure energy.
6. B – In beta-minus decay, a neutron becomes a proton, increasing the atomic number by 1.
7. C – Gamma rays are the most penetrating; they require dense materials to block.
8. C – A Geiger-Müller counter detects radioactive emissions.
9. C – Half-life is the time it takes for half of the radioactive atoms in a sample to decay.
10. B – 100 g → 50 g (10 yrs) → 25 g (20 yrs).
11. C – Carbon-14 is used to date once-living materials like fossils.
12. B – Radioactive decay releases energy; it is exothermic.
13. B – Alpha decay removes 2 protons and 2 neutrons; atomic number drops by 2.
14. B – Radiation causes ionization in living tissues, damaging DNA and cells.
15. B – Beta particles (electrons) have less mass and are deflected more in a magnetic field.
16. C – Radioisotopes are used in imaging (PET scans) and cancer treatment (radiotherapy).
17. C – Transmutation is the transformation of one element into another via decay.
18. C – Gamma rays are the least ionizing but most penetrating.
19. C – A beta particle is a high-speed electron ejected from a nucleus.
20. D – Gamma rays require thick layers of lead or concrete for effective shielding.
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