Home › Worksheets › A Level Year 13 Physics › Nuclear Physics Prepared by Mohsim Digital Education
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The mass number of a nucleus is the number of protons and neutrons, and an alpha particle is a helium nucleus, so this Year 13 sheet opens with the nucleus count and the alpha identity. The answers add beta as a fast-moving electron and becquerel as the activity unit.
Key Takeaways
Mass number = protons + neutrons (Q1).
An alpha particle is a helium nucleus (Q2).
Q3 records beta as a fast-moving electron.
Section A: Multiple Choice Questions (1 Mark Each)
Choose the correct option for each question.
1.
The mass number of a nucleus is the number of...
(a) protons only (b) protons and neutrons (c) neutrons only (d) electrons and protons
2.
An alpha particle is...
(a) an electron (b) a helium nucleus (c) a photon (d) a neutron
3.
A beta-minus particle is...
(a) a fast-moving electron (b) a positron (c) a helium nucleus (d) a gamma photon
4.
Gamma radiation consists of...
(a) high-energy electrons (b) high-energy electromagnetic waves (c) helium nuclei (d) free neutrons
5.
Which type of radiation has the greatest ionising power?
(a) alpha (b) beta (c) gamma (d) X-rays
6.
The unit of activity of a radioactive source is the...
(a) joule (b) watt (c) becquerel (d) coulomb
Section B: Short Answer Type Questions (2 Marks Each)
Show all steps clearly.
7.
Define isotope.
8.
Define the activity of a radioactive source.
9.
What is an alpha particle composed of?
10.
State the nature and charge of a beta-minus particle.
11.
Why is gamma radiation the most penetrating type of radiation?
12.
Write down the equation relating activity, decay constant and the number of undecayed nuclei.
13.
Define half-life.
14.
What happens to the atomic number and mass number of a nucleus when it emits an alpha particle?
Section C: Numericals & Word Problems (3 Marks Each)
Apply the concepts to solve the problems. Show all working.
15.
A sample has an initial activity of 400 Bq and a half-life of 8 days. After 24 days (three half-lives), calculate its activity.
16.
A radioactive isotope has a half-life of 5730 years. Using λ = 0.693/T½, calculate its decay constant in year⁻¹.
17.
A sample contains 1.2×10²⁰ undecayed nuclei with a decay constant of 1.5×10⁻⁴ s⁻¹. Using A = λN, calculate the activity.
18.
A mass of 1×10⁻⁶ kg is completely converted into energy. Using E = mc² with c = 3×10⁸ m s⁻¹, calculate the energy released.
19.
A nuclear event releases 200 MeV of energy. Given that 1 MeV = 1.6×10⁻¹³ J, calculate the energy released in joules.
20.
The activity of a source falls from 800 Bq to 100 Bq in 36 days. Find the number of half-lives that have passed and hence the half-life.
Answer Key
1. b) protons and neutrons
2. b) a helium nucleus
3. a) a fast-moving electron
4. b) high-energy electromagnetic waves
5. a) alpha
6. c) becquerel
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End of Worksheet
People Also Ask
What does the mass number of a nucleus count?
Protons and neutrons, option (b) in this worksheet (Q1).
What is an alpha particle?
A helium nucleus, option (b) in this worksheet (Q2).
What is a beta particle?
A fast-moving electron, option (a) in this worksheet (Q3).