Question 1: Define nuclear fission in your own words.

Answer: Nuclear fission is a process in which a heavy nucleus splits into two smaller nuclei, releasing a large amount of energy and neutrons.

Question 2: Explain why neutrons are used to initiate fission in a nuclear reactor.

Answer: Neutrons are uncharged particles that can penetrate the nucleus easily and can initiate fission without being repelled by the nucleus's positive charge.

Question 1: Calculate the energy released when 1 gram of uranium-235 undergoes fission. (Use the approximation that 1 kg of uranium releases 8.2 × 10^{13} Joules of energy).

Answer: Energy = 8.2 × 10^{13} J/kg × 0.001 kg = 8.2 × 10^{10} Joules

Question 2: If a reactor produces 500 MW of power continuously for 24 hours, how much energy is generated in joules?

Answer: Energy = Power × Time = 500 × 10^{6} W × 24 × 3600 seconds = 4.32 × 10^{12} Joules

Question 1: List three safety precautions that must be taken when handling fissile materials in a laboratory setting.

Answer: Use shielding to block radiation, wear protective clothing and gloves, and implement strict access controls to fissile materials.

Question 2: Explain why cooling systems are essential in a nuclear fission reactor.

Answer: Cooling systems remove excess heat generated during fission to prevent overheating, which could lead to reactor damage or meltdowns.

Question 1: A sample of uranium-235 undergoes fission, releasing an average of 200 MeV of energy per reaction. How many reactions are needed to produce 1 Joule of energy?

Answer: Number of reactions = 1 Joule / (200 MeV to Joules) = 1 / (200 × 1.602 × 10^{-13}) ≈ 3.12 × 10^{12} reactions

Question 2: In a controlled reactor, the rate of fission reactions is 10^{20} reactions per second. Discuss how this rate affects the power output and potential safety considerations.

Answer: A fission rate of 10^{20} reactions per second results in a very high power output, requiring effective cooling and control systems to prevent overheating and meltdowns. Maintaining a steady reaction rate ensures safe energy production and prevents runaway reactions.

Question 1: Describe how nuclear fission is utilised in nuclear power plants to generate electricity.

Answer: In nuclear power plants, controlled fission reactions release heat, which is used to produce steam that drives turbines connected to generators, producing electricity.

Question 2: Identify one advantage and one disadvantage of using nuclear fission as an energy source.

Answer: Advantage: Produces large amounts of energy with low greenhouse gas emissions. Disadvantage: Produces radioactive waste requiring long-term management.