Form 5 Physics Bab 6: Nuclear Physics
Instructions
Answer all structured questions. Show clear working for numerical problems. Take 1 u = 1.66 × 10⁻²⁷ kg and c = 3.0 × 10⁸ m s⁻¹ where applicable.
10 questions · 27 marks total
1. Which of the following components in a nuclear power reactor slows down fast neutrons produced during fission to enable a continuous chain reaction?
Multiple Choice · 1m2. Fill in the blank: The time required for half of the initial number of unstable radioactive nuclei in a sample to decay is known as its ________.
Fill in the Blank · 1m3. A radioactive radiation source emits alpha, beta, and gamma radiation simultaneously. (a) State how you would separate the three radiations using an electric field. (b) Which radiation will pass through undeflected and why?
Short Answer · 3m4. Safety in a nuclear reactor relies on various engineered safety barriers: (a) What material is used for control rods and what is its operational function during an emergency shutdown? (b) Why is thick reinforced concrete wall shielding constructed around the reactor core?
Short Answer · 4m5. True or False: Nuclear fusion involves splitting a heavy nucleus into two lighter nuclei accompanied by a massive release of energy.
True / False · 1m6. Compare nuclear fission and nuclear fusion: (a) State ONE difference between the two processes in terms of the reactant nuclei involved. (b) State ONE similarity between the two processes regarding energy production.
Short Answer · 3m7. The following nuclear equation represents a nuclear fission reaction: ²³⁵₉₂U + ¹₀n -> ¹₄¹₅₆Ba + ⁹²₃₆Kr + 3(¹₀n) + Energy Mass of U-235 = 235.0439 u, Neutron = 1.0087 u, Ba-141 = 140.9144 u, Kr-92 = 91.9261 u. (a) Calculate the mass defect (Δm) in atomic mass units (u). (b) Calculate the nuclear energy released in Joules (J).
Short Answer · 5m8. A radioactive sample initially contains 120 g of Iodine-131, which has a half-life of 8 days. (a) Define half-life. (b) Calculate the mass of Iodine-131 remaining after 32 days. (c) How long will it take for the sample to decay until only 3.75 g remains?
Short Answer · 4m9. The nuclear fusion reaction in the Sun fuses Deuterium (²₁H) and Tritium (³₁H) to form Helium (⁴₂He) and a neutron (¹₀n). Given: Mass of ²₁H = 2.0141 u, ³₁H = 3.0160 u, ⁴₂He = 4.0026 u, ¹₀n = 1.0087 u. (a) Write the balanced nuclear equation for this fusion reaction. (b) Calculate the energy released in this reaction in Joules.
Short Answer · 4m10. True or False: Gamma rays carry a negative electric charge and are easily deflected by a magnetic field.
True / False · 1m