Question

(a) How are electromagnetic waves produced?
(b) Write the wavelength range and one use of:
(i) Microwaves, and
(ii) Ultraviolet waves.

Hint:

Electromagnetic waves arise due to accelerating charges. Microwaves are used for communication; UV rays are useful for disinfection due to their high energy.

Answer 1

(a) Production of Electromagnetic Waves: Electromagnetic waves are produced by the acceleration of electric charges. When a charged particle (like an electron) accelerates, it creates a time-varying electric field. This changing electric field induces a changing magnetic field, and vice versa. This mutual generation leads to the propagation of electromagnetic waves. Thus, an accelerated charge emits electromagnetic radiation. (b) Wavelength Range and Uses: (i) Microwaves: \begin{itemize} \item Wavelength range: \( \sim 1\,\text{mm} \) to \( 30\,\text{cm} \) \item Use: Used in radar systems, microwave ovens, and satellite communication. \end{itemize} (ii) Ultraviolet (UV) Waves: \begin{itemize} \item Wavelength range: \( \sim 10\,\text{nm} \) to \( 400\,\text{nm} \) \item Use: Sterilization of medical instruments and water purification. \end{itemize}