Harmful radiation emitted by the sun is ____.
Visible
Infrared
Ultraviolet
Radio wave
Which of the following are used in electric water filters to kill all the harmful micro-organisms present in tap water and make it absolutely safe for drinking?
(a) infrared radiation
(b) gamma radiation
(c) visible radiation
(d) ultraviolet radiation
State one harmful effect each of the (a) ultraviolet and (b) infrared radiations.