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) Electromagnetic Wave Generation: Electromagnetic waves are generated when electric charges accelerate. An accelerating charged particle, such as an electron, produces a fluctuating electric field. This changing electric field subsequently generates a changing magnetic field, and this process is reciprocal. This self-sustaining interaction allows electromagnetic waves to propagate. Consequently, an accelerated charge radiates electromagnetic energy. (b) Wavelength Spectrum and Applications: (i) Microwaves:

• Wavelength range: \( \sim 1\,\text{mm} \) to \( 30\,\text{cm} \)
• Applications: Employed in radar, microwave ovens, and satellite communications.

(ii) Ultraviolet (UV) Waves:

• Wavelength range: \( \sim 10\,\text{nm} \) to \( 400\,\text{nm} \)
• Applications: Utilized for sterilizing medical equipment and purifying water.