Question 1: A chain reaction in nuclear physics occurs when one nuclear reaction initiates further reactions, releasing a large amount of energy. In nuclear reactors, controlled chain reactions are used to produce energy. Explain in your own words how a neutron can trigger a chain reaction in uranium-235.

Answer: A neutron collides with a uranium-235 nucleus, causing it to become unstable and split (fission), releasing more neutrons that can then trigger further fissions.

Question 1: Define nuclear chain reaction.

Answer: A self-sustaining series of nuclear fissions where emitted neutrons trigger further fissions.

Question 2: What is the primary particle involved in initiating a chain reaction in nuclear fission?

Answer: Neutron

Question 3: Name one isotope commonly used in nuclear reactors to sustain chain reactions.

Answer: Uranium-235

Question 1: If 1 neutron causes the fission of 1 uranium-235 nucleus and releases 200 MeV of energy, how much energy is released when 10,000 atoms undergo fission? (Use the formula: Total Energy = Number of atoms × Energy per fission)

Answer: Total Energy = 10,000 × 200 MeV = 2,000,000 MeV

Question 2: A nuclear reactor has a neutron multiplication factor (k) of 1.2. What does this value indicate about the chain reaction?

Answer: It indicates the reaction is supercritical, with the chain reaction increasing and releasing more energy over time.

Question 1: Describe the safety precautions that should be taken when handling materials involved in nuclear chain reactions.

Answer: Use shielding to block radiation, wear protective clothing, limit exposure time, handle materials remotely, and follow strict safety protocols to prevent radiation exposure.

Question 1: In a hypothetical reactor, the number of neutrons produced per fission is 2.5, and the number of neutrons lost per cycle is 1.5. Calculate the effective neutron multiplication factor (k).

Answer: k = Neutrons produced / Neutrons lost = 2.5 / 1.5 ≈ 1.67

Question 1: Explain how controlled chain reactions are used in nuclear power plants to generate electricity.

Answer: Controlled chain reactions in nuclear power plants use moderators and control rods to regulate neutron flow, ensuring the reaction remains steady. The energy released from fission heats water to produce steam, which drives turbines to generate electricity efficiently and safely.

Question 2: Identify at least two advantages and two disadvantages of using nuclear chain reactions for energy production.

Answer: Advantages: High energy output, low greenhouse gas emissions. Disadvantages: Radioactive waste, risk of accidents.