Explanation

• A quantum of energy of light (electromagnetic radiation) is called a photon.

• Photon is the smallest discrete packet (bundle) of energy.

• It carries energy proportional to its frequency (E = hf).

• Photons have no mass and travel at the speed of light.

• Light shows particle nature due to photons.

Last verified on 09-05-2026

Explanation

• Photoelectric emission stops when the frequency of incident light is below the threshold frequency of the metal.

• Below this minimum frequency, electrons cannot gain enough energy to escape the metal surface.

• Each metal has its own threshold frequency.

• This effect supports the quantum theory of light.

Last verified on 09-05-2026

Explanation

• Spring tides occur when the Earth, Moon, and Sun are in a straight line (aligned).

• This happens during New Moon and Full Moon phases.

• The gravitational pull of the Moon and Sun combines, producing very high and very low tides.

• Spring tides are not related to seasons like spring; the name refers to “jumping or rising” tides.

• They occur about twice a month.

Last verified on 09-05-2026

Explanation

• Laser light is intense because its light waves are coherent, meaning they remain in the same phase and travel together.

• Coherent waves combine their energy, producing a strong and focused beam.

• LASER stands for “Light Amplification by Stimulated Emission of Radiation.”

• Laser light differs from ordinary light because it is highly directional and monochromatic.

• Due to very little spreading, laser beams can travel long distances with high intensity.

Last verified on 09-05-2026

Explanation

• Beta radiation has intermediate penetrating power between alpha and gamma rays.

• Alpha rays have the least penetrating power, while gamma rays have the highest.

• Beta particles can pass through paper but are stopped by thin aluminum sheets.

• Beta radiation consists of fast-moving electrons or positrons.

• Ernest Rutherford classified alpha and beta radiations during radioactive studies.

Last verified on 09-05-2026