What are ultra violet radiations? How are they detected? State one use of these radiations.

An electromagnetic wave has a frequency of 500 MHz and a wavelength of 60 cm.

(a) Calculate the speed of the wave.

(b) Name the medium through which it is travelling.

For scattering of light, the necessary condition is that the size of air molecules should be …………… the wavelength of incident light.

1. smaller than
2. greater than
3. equal to
4. both (b) and (c)