πŸ“Š Physics
Q. Which of the following has the least mass?
  • (A) Proton
  • (B) Neutron
  • (C) Electron
  • (D) Alpha particle
πŸ’¬ Discuss
βœ… Correct Answer: (C) Electron

Explanation: Electron has the least mass among the given particles, approximately 1/1836 of a proton.

πŸ“Š Physics
Q. Which nuclear reaction is responsible for the energy of the sun?
  • (A) Nuclear fission
  • (B) Nuclear fusion
  • (C) Radioactive decay
  • (D) Ionization
πŸ’¬ Discuss
βœ… Correct Answer: (B) Nuclear fusion

Explanation: The Sun’s energy comes from the fusion of hydrogen nuclei into helium, releasing enormous energy.

πŸ“Š Physics
Q. Which of the following isotopes is used in nuclear power plants for generating electricity?
  • (A) Uranium-235
  • (B) Carbon-14
  • (C) Deuterium
  • (D) Hydrogen-1
πŸ’¬ Discuss
βœ… Correct Answer: (A) Uranium-235

Explanation: Uranium-235 undergoes controlled fission in nuclear power plants to produce electricity.

πŸ“Š Physics
Q. What is radioactivity?
  • (A) Emission of light from hot objects
  • (B) Spontaneous emission of particles from unstable nuclei
  • (C) Absorption of radiation by atoms
  • (D) Production of energy by friction
πŸ’¬ Discuss
βœ… Correct Answer: (B) Spontaneous emission of particles from unstable nuclei

Explanation: Radioactivity is the spontaneous disintegration of unstable atomic nuclei with emission of radiation.

πŸ“Š Physics
Q. Which scientist discovered radioactivity?
  • (A) Marie Curie
  • (B) Henri Becquerel
  • (C) Rutherford
  • (D) Einstein
πŸ’¬ Discuss
βœ… Correct Answer: (B) Henri Becquerel

Explanation: Henri Becquerel discovered natural radioactivity in 1896 while studying uranium salts.

πŸ“Š Physics
Q. What type of radiation is deflected the most by a magnetic field?
  • (A) Alpha rays
  • (B) Beta rays
  • (C) Gamma rays
  • (D) Neutrons
πŸ’¬ Discuss
βœ… Correct Answer: (B) Beta rays

Explanation: Beta particles have small mass and high velocity, so they are deflected most in a magnetic field.

πŸ“Š Physics
Q. Which radioactive element is used in smoke detectors?
  • (A) Uranium
  • (B) Plutonium
  • (C) Americium-241
  • (D) Thorium
πŸ’¬ Discuss
βœ… Correct Answer: (C) Americium-241

Explanation: Americium-241 emits alpha particles that ionize air, helping detect smoke in alarm systems.

πŸ“Š Physics
Q. Which type of nuclear radiation has the least penetrating power?
  • (A) Alpha rays
  • (B) Beta rays
  • (C) Gamma rays
  • (D) X-rays
πŸ’¬ Discuss
βœ… Correct Answer: (A) Alpha rays

Explanation: Alpha particles can be stopped by a sheet of paper or even human skin.

πŸ“Š Physics
Q. The energy released per fission of a uranium nucleus is approximately:
  • (A) 1 eV
  • (B) 1 MeV
  • (C) 200 MeV
  • (D) 2000 MeV
πŸ’¬ Discuss
βœ… Correct Answer: (C) 200 MeV

Explanation: Each uranium-235 fission releases about 200 MeV of energy in the form of kinetic energy and radiation.

πŸ“Š Physics
Q. What is the main coolant used in pressurized water reactors (PWR)?
  • (A) Carbon dioxide
  • (B) Heavy water
  • (C) Light water
  • (D) Liquid sodium
πŸ’¬ Discuss
βœ… Correct Answer: (C) Light water

Explanation: Pressurized water reactors use light water as both coolant and moderator.

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