Question

How fast do different parts of EM spectrum travel in a vacuum ?

Answer 1

Hint: In electromagnetic spectrum, the spectrum is differentiated according to the wavelength and the frequency of the waves. The electromagnetic waves are the transverse waves. These waves are formed as a result of electric and magnetic fields. The resultant wave is propagated in a transverse direction. Hence these waves are also called transverse waves.

Complete answer:
(i) The electromagnetic spectrum consists of visible light, microwaves, radio-waves, UV rays, IR rays, Gamma rays, etc… The maximum velocity one can attain is the velocity of light. In the electromagnetic spectrum, all parts of the spectrum have the same amount of speed while travelling in a vacuum.
(ii) We know that the speed of light, C is equal to the product of wavelength and the frequency. If the wavelength increases, the frequency decreases. Hence the speed remains the same for all parts of the electromagnetic spectrum in a vacuum.
(iii) The velocity changes between the various parts of the spectrum only while travelling in a different medium. Hence the velocity differs according to the refractive index of the medium.
(iv)Therefore the velocity of the electromagnetic spectrum is equal to the velocity of the light. The velocity of light is measured as \[3 \times {10^8}\,m/{s^2}\].

Note:The electromagnetic waves are formed as a resultant of electric and magnetic fields. The resultant transverse wave is called electromagnetic waves. The electromagnetic waves travel at a speed of light in a vacuum. The speed of light is equal to \[3 \times {10^8}\,m/{s^2}\]. The speed only changes when the EM wave is travelling in different mediums.