Nuclear Physics and Energy

Thermonuclear runaway occurs when uncontrolled fusion reactions convert hydrogen into helium in stellar cores, releasing enormous energy. This process powers stars and can lead to supernovae.

All three are nuclear reactors at BARC (Bhabha Atomic Research Centre). Apsara was India's first nuclear reactor (critical in 1956), Purnima-1 was a plutonium-based reactor, and Kamini is a uranium-233 fueled reactor. Therefore 'All the above' is the correct answer.

The Trinity test was the first-ever nuclear detonation, conducted by the United States on July 16, 1945 in New Mexico as part of the Manhattan Project. 'Ranger' and 'Ivy' were later nuclear test series, not individual tests. 'Greenhouse' was another test series in 1951, well after Trinity.

Options A, B, and C all describe real obstacles to nuclear energy development (high costs, safety risks, waste disposal). Option D claims nuclear power is clean and cheap - while it has low emissions, 'cheap' is debatable and this statement doesn't describe an OBSTACLE, making it the correct answer to the NOT question.

The power of nuclear weapons and large explosives is measured in megatons of TNT, where one megaton equals the energy released by one million tons of TNT. Kilotons (thousands of tons) are used for smaller nuclear weapons, while gigatons would be impractically large.

The bomb dropped on Nagasaki (Fat Man) used plutonium-239 as its core. The Hiroshima bomb (Little Boy) used uranium-235, which is a common point of confusion.

Uranium-235 constitutes only about 0.7% of natural uranium, making its extraction extremely difficult and resource-intensive. The Manhattan Project employed multiple complex enrichment techniques like gaseous diffusion and electromagnetic separation to isolate U-235 from the abundant U-238 isotope.

Uranium is the correct answer. It is the primary fuel used in nuclear power plants, where uranium-235 undergoes fission to release energy. While some plants use thorium (experimental) or plutonium (breeder reactors), uranium is overwhelmingly the main commercial fuel.

All three - Apsara (Asia's first nuclear reactor), Purnima-1, and Kamini - are atomic reactors developed by BARC (Bhabha Atomic Research Centre). Each represents different generations of India's nuclear research capabilities.

During the meteor shower on the asteroid (the 'rock storm'), debris damages the bomb's remote triggering mechanism, which is why someone must stay behind to detonate it manually. This is a key plot point that creates the central conflict.

Uranium-238 is the most abundant isotope of uranium but is NOT suitable for nuclear fission reactors because it is not fissile - it does not readily undergo fission when struck by thermal neutrons. Uranium-235 and Plutonium-239 are the preferred fissile materials used in nuclear reactors and weapons.

USS Nautilus, launched in 1954, was the world's first operational nuclear-powered submarine. Its nuclear reactor allowed it to remain submerged for much longer periods than diesel-electric submarines and travel faster underwater, revolutionizing naval warfare during the Cold War.