With reference to radioisotope thermoelectric generators (RTGs), consider the following statements: 1. RTGs are miniature fission reactors. 2. RTGs are used for powering the onboard systems of spacecrafts. 3. RTGs can use Plutonium-238, which is a by-product of weapons development. Which of the statements given above are correct?

Answer: B. Statements 2 and 3 are correct; Statement 1 is wrong. Statement 1 is WRONG. RTGs are NOT fission reactors. They generate electricity by converting heat from the natural RADIOACTIVE DECAY (not fission) of an isotope into electric power via thermocouples (the Seebeck effect). No fission chain reaction is involved. Statement 2 is CORRECT. RTGs are widely used to power spacecraft systems on deep-space missions (Voyager 1 and 2, Cassini, New Horizons, Curiosity and Perseverance Mars rovers). They are reliable in low-sunlight environments where solar panels are impractical. Statement 3 is CORRECT. RTGs commonly use Plutonium-238, which is a by-product of nuclear weapons production (specifically the production of weapons-grade Pu-239 via neutron capture). Source: NASA RTG technical documentation / DOE Plutonium-238 supply program.