Question

A microwave oven uses -; 1) infrared rays; 2) ultraviolet rays; 3) radio waves of very short wavelengths; 4) radio waves of long wavelengths

Answer 1

Electromagnetic spectrum, the entire distribution of electromagnetic radiationaccording to frequency or wavelength. Although all electromagnetic waves travel at the speed of lightin a vacuum, they do so at a wide range of frequencies, wavelengths, and photon energies. The electromagnetic spectrumcomprises the span of all electromagnetic radiation and consists of many subranges, commonly referred to as portions, such as visible light or ultraviolet radiation. The various portions bear different names based on differences in behaviour in the emission, transmission, and absorption of the corresponding waves and also based on their different practical applications. There are no precise accepted boundaries between any of these contiguous portions, so the ranges tend to overlap.