Question

Electromagnetic waves of wavelengths λ₁, λ₂ and λ₃ are used in a radar system, in water purifiers and in remote switches of TV, respectively.

1. Identify the electromagnetic waves.
2. Write one source for each of them.

Answer 1

(i)

• Wavelength λ₁ corresponds to Microwaves.
• Wavelength λ₂ corresponds to Ultraviolet waves.
• Wavelength λ₃ corresponds to Infrared waves.

(ii)

• Source of microwaves: Klystron/magnetron valves.
• Source of ultraviolet waves: Movement of electrons in atoms from higher energy level to lower energy level.
• Source of infrared waves: Vibration of atoms and molecules.