Question

How are infrared waves produced? Why are these waves referred to as heat waves? Give any two uses of infrared waves.

How are X-rays produced? Give any two uses of these.

Write two uses of any two of these radiation.

(a) "The wavelength of the electromagnetic wave is often correlated with the characteristic size of the system that radiates." Give two examples to justify this statement. (b) (i) Long distance radio broadcasts use short-wave bands. Why ? (ii) Optical and radio telescopes are built on the ground, but X-ray astronomy is possible only from satellites orbiting the Earth. Why ?