Atomic and Nuclear Physics
X-rays can pass through
  • Carbon
  • Gold
  • Both A and D
  • Calcium
Explanation: X-rays can pass through Carbon andCalcium, but they are largely absorbed by (B) Gold and (C) Lead, with lead being the most effective in blocking X-rays.
___ rays are used in the treatment of skin disorders.
  • Gamma rays
  • UV rays
  • IR rays
  • X rays
Explanation: Ultraviolet (UV) rays are used in the treatment of various skin disorders, such as psoriasis, eczema, and vitiligo, through phototherapy.
Protons and neutrons in the nucleus are called as
  • Positron
  • Electron
  • Nucleons
  • Nucleus
Explanation: Nucleons refer to the protons and neutrons present in the nucleus of an atom.
Particles like mesons were discovered from
  • elementary particles
  • gamma rays
  • cosmic ray showers
  • cosmic rays
Explanation: Mesons were first discovered in cosmic ray showers, where high-energy cosmic rays collide with atmospheric particles, creating secondary particles, including mesons. Key Points: Cosmic Ray Showers: High-energy cosmic rays from space interact with Earth's atmosphere, producing a cascade of secondary particles, including mesons. Discovery of Mesons: The pion (π-meson) was first discovered in cosmic rays, confirming Yukawa's theory of nuclear forces.
Who named the ionising radiations from outer cosmos as cosmic rays?
  • Irene Curie
  • Millikan
  • Sommerfeld
  • Neil Bohr
Explanation: Robert A. Millikan named the ionizing radiations from outer space as cosmic rays in the early 20th century while studying high-energy radiation penetrating the Earth's atmosphere.
The principle used in Atom bomb is
  • nuclear interaction
  • nuclear fusion
  • nuclear fission
  • none of the above
Explanation: The atom bomb works on the principle of nuclear fission, where a heavy nucleus (like uranium-235 or plutonium-239) splits into smaller nuclei, releasing a huge amount of energy in the form of an explosion.
1 amu is equal to
  • 1.66 × 10⁻²⁷ kg
  • Explanation: 1 atomic mass unit (amu) is approximately 1.66 × 10⁻²⁷ kg, which is the average mass of a nucleon (proton or neutron) in an atom.