Question

What rays exist beyond the visible red end of the
electromagnetic spectrum? State one use and one
method of detecting these rays.​

Answer 1

Answer:

Beyond visible-red end of electromagnetic spectrum, infra-red rays exist. Infra-red rays have wavelength greater than and frequency less than that of red light.

Use: Infra-red rays are very penetrating; hence infrared cameras are used during foggy season and during war time by flying plane high enough to avoid attack by anti-aircraft guns.

Detection: Since they contain a good amount of heat rays, hence these can be detected by thermometer whose bulb is coated black. When the bulb is moved from violet to red, there is a large increase in temperature. This is due to heat contained in infra-red rays.