→At the time when Maxwell predicted the existence of EM waves, the only familiar EM waves were the visible light waves.
→The existence of ultraviolet waves (u.v.) and infrared (I.R.) waves was hardly established. By the end of the nineteenth century, x-rays and gamma rays had also been discovered.
→We now know that, EM waves include visible light waves, x-rays, gamma rays, radio waves, micro waves, ultraviolet and infrared waves.
→The classification of EM waves according to frequency is called Electro magnetic spectrum, which is shown in the figure.
