Which of the following statements is/are correct?

(a) Infrared waves are produced by hot bodies.

(b) Sun is an important source of ultraviolet light.

Concept:

Infrared wave:

• Infrared waves are produced by hot bodies and molecules.
• They are referred to as heat waves because they are readily absorbed by water molecules in most materials which increases their thermal motion so they heat up the material.
• Infrared is used for therapeutic purposes and long-distance photography.

Ultraviolet ray:

• Ultraviolet (UV) is a form of electromagnetic radiation with a wavelength from 10nm (with a corresponding frequency of around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays.
• Sun is the main source of UV rays.
• UV radiation is present in sunlight and constitutes about 10% of the total electromagnetic radiation output from the Sun
• UV rays burn the skin and can cause skin cancer.
• It is the ozone layer that protects us from harmful UV rays.

​Explanation:

• Infrared waves are produced by hot bodies and molecules.
• Infrared is the thermal emission (or heat) from our planet.
• As incident solar radiation hits Earth, some of this energy is absorbed by the atmosphere and the surface, thereby warming the planet.
• This heat is emitted from Earth in the form of infrared radiation.
• Sun is the main source of Ultraviolet light.