Question 1: Define nuclear fusion and explain how it differs from nuclear fission.

Answer: Nuclear fusion is the process where two light atomic nuclei combine to form a heavier nucleus, releasing energy. It differs from fission, where a heavy nucleus splits into lighter nuclei.

Question 2: Name the most common isotopes involved in fusion reactions that occur in the Sun.

Answer: Hydrogen isotopes, mainly deuterium and tritium.

Question 3: Describe the main advantage of fusion over nuclear fission as an energy source.

Answer: Fusion produces less long-lived radioactive waste and has an abundant fuel supply, making it safer and more sustainable.

Question 1: Calculate the energy released when 1 gram of deuterium (D) nuclei undergo fusion, given that the fusion of deuterium releases approximately 3.3 MeV of energy per reaction. (Use 1 MeV = 1.602 x 10^-13 Joules).

Answer: Energy = (Number of reactions) x (Energy per reaction); Number of reactions = mass of deuterium / mass of one deuterium nucleus. Mass of deuterium nucleus ≈ 2.014 u = 3.34 x 10^-27 kg. Number of deuterium nuclei in 1 g (0.001 kg) = 0.001 / 3.34 x 10^-27 ≈ 2.99 x 10^23. Total energy = 2.99 x 10^23 x 3.3 MeV x 1.602 x 10^-13 J/MeV ≈ 1.59 x 10^11 Joules.

Question 2: If a fusion reactor produces 500 MW of power continuously, how much energy does it generate in 24 hours? Express your answer in Joules.

Answer: Power = 500 MW = 500 x 10^6 W. Energy = Power x Time = 500 x 10^6 W x 24 x 3600 seconds = 4.32 x 10^13 Joules.

Question 1: List three safety precautions that must be taken when designing a fusion reactor.

Answer: Proper shielding to protect against neutron radiation, careful handling of tritium fuel due to its radioactivity, and maintaining strong magnetic confinement to prevent accidental release of hot plasma.

Question 2: Describe a basic experimental setup used to study nuclear fusion reactions in a laboratory setting.

Answer: A typical setup involves a magnetic confinement device like a tokamak or a laser-induced inertial confinement system, where fuel pellets are heated and compressed to achieve the required temperature and pressure for fusion. Safety measures include shielding, remote handling, and controlling plasma stability.

Question 1: A fusion experiment produces 5 x 10^14 joules of energy over a period of 30 days. Calculate the average power output in Watts and discuss whether this is feasible for a commercial power plant.

Answer: Total energy = 5 x 10^14 Joules. Time = 30 days = 30 x 24 x 3600 = 2.592 x 10^6 seconds. Average power = Total energy / time = 5 x 10^14 / 2.592 x 10^6 ≈ 1.93 x 10^8 Watts (193 MW). This level of power output is within the range of modern large-scale power plants, indicating potential feasibility if sustained efficiently.

Question 1: Explain the process of nuclear fusion in the Sun, including the role of temperature, pressure, and isotopes involved. Discuss the challenges scientists face in replicating this process on Earth and how current research aims to overcome these challenges.

Answer: Nuclear fusion in the Sun occurs when high temperatures (~15 million °C) and immense pressure cause hydrogen nuclei (mainly isotopes like deuterium and tritium) to overcome electrostatic repulsion and fuse, releasing large amounts of energy. On Earth, replicating this requires achieving similar temperatures and pressures, which is technologically challenging due to material limits and energy input requirements. Current research focuses on magnetic confinement devices like tokamaks and inertial confinement methods, aiming to sustain plasma stability and achieve net energy gain, thereby making fusion a viable energy source.

Question 1: Describe two potential advantages of nuclear fusion as a future energy source in terms of environmental impact and fuel availability.

Answer: Fusion produces minimal greenhouse gases and generates less long-lived radioactive waste. Its fuel, mainly isotopes of hydrogen like deuterium, is abundant in seawater, ensuring a sustainable supply.

Question 2: Discuss how advancements in fusion technology could influence global energy policies in the next 50 years.

Answer: Advancements could lead to the development of clean, abundant, and sustainable energy sources, reducing reliance on fossil fuels and decreasing greenhouse gas emissions. This may influence policies to promote fusion research, international collaboration, and investment in fusion power plants, ultimately contributing to global efforts to combat climate change and ensure energy security.