Question

What form of light is closely related to heat? (a) U.V. (b) Infrared (c) Radio Waves (d) Gamma rays

Answer 1

Infrared.

Explanation:

The energy of a photon is given by `hnu`, where`h` is Planck's constant and `nu` is the frequency of eleectromagnetic radiations.

Although all electromagnetic waves or photons will heat an object, when absorbed, a photon from infrared raange has an energy of the order of the energy of vibrational transitions in molecules and hence it is absorbed better.

Hence, infrared is more associated with heat.

Answer 2

Infrared electromagnetic radiation is invisible and has wavelength just greater than that of the red colour of the visible light spectrum but less than that of microwaves.

Infrared radiation has a wavelength from about `800 nm" to "1 mm`, and is emitted particularly by heated objects.