Radioactive Decay Quiz

1. What is a beta particle?

• A. A helium nucleus
• B. A fast-moving electron
• C. A form of electromagnetic radiation
• D. A neutron ejected from the nucleus

2. Which type of radiation is stopped by only a sheet of paper?

• A. Alpha
• B. Beta
• C. Gamma
• D. None of them

3. Why is gamma radiation not deflected by a magnetic field, unlike alpha and beta particles?

• A. It travels too fast to be deflected
• B. It is electromagnetic radiation and carries no charge
• C. It is heavier than alpha and beta particles
• D. Magnetic fields only affect particles emitted from stable nuclei

4. An unstable nucleus undergoes beta decay. What happens to its proton number and nucleon number, and what physically occurs inside the nucleus to cause this?

• A. Proton number decreases by 1, nucleon number unchanged; a proton turns into a neutron
• B. Proton number increases by 1, nucleon number unchanged; a neutron turns into a proton, releasing an electron
• C. Proton number decreases by 2, nucleon number decreases by 4; two neutrons are ejected
• D. Proton number and nucleon number both stay the same; only energy is released

5. A sample emits radiation that is only slightly deflected by a magnetic field, in the same direction as a beam of protons would deflect, and is stopped by a few centimetres of air. Identify the type of radiation and justify your answer using both pieces of evidence.

• A. Gamma radiation, because gamma rays deflect in the same direction as protons
• B. Alpha radiation, because it is positively charged (deflecting the same way as protons) and its short range in air matches its weak penetrating power
• C. Beta radiation, because electrons deflect in the same direction as protons in a magnetic field
• D. Neutron radiation, because neutrons are undeflected by magnetic fields but stopped easily by air