(i) Microwaves are suitable for RADAR systems that
are used in aircraft navigation. These rays are produced by special vacuum tubes, namely klystrons, magnetrons and gunn diodes.
(ii) Infrared rays are used to treat muscular strain. These rays are produced by hot bodies and molecules.
(iii) X-rays are used as a diagnostic tool in medicine.
These rays are produced when high energy electrons are stopped suddenly on a metal of high atomic