What are the uses of Infra red waves ?

Explanation

(i) Infra red lamps are used in physiotherapy.
(ii) Infra red photographs are used in weather forecasting.
(iii) As infra red radiations are not absorbed by air, thick fog, mist, etc., they are used to take photograph of long distance objects.
(iv) Infra red absorption spectrum is used to study the molecular structure.