how does infa-red radiation cause heating when absorbed by any object and how is it used in radiant heaters?

Answer 1

Infrared (IR) radiation is a form of electromagnetic radiation, like light and radio waves. All electromagnetic radiation can be and is absorbed by anything, but the effects depend on the type of radiation.

IR rays cause heating by causing the electrons in an atom to vibrate faster than it already is. Imagine a guitar string that is already vibrating, making a sound. If you pluck the string a bit the string will vibrate more, creating a louder sound. Now if you compare the string to an electron in an atom, then your finger would be the IR ray. The initial vibration can then be compared to the energy of the atom, and the final vibration is the energy of the atom after being exposed to IR rays. The louder the sound, the more energy the string has. In the same manner, the more energy an atom has, the warmer an object is.

Answer 2

There are basically two forms of heater. Radiant and convection.
Either type will heat up an object that is capable of absorbing heat, it is just the radiant heat tends to be more concentrated.
A radiator, as in central heating, works in both ways. The hot surface of the radiator emits radiated heat and the air passing over it forms convection currents which warm the air and thus the room. True radiant heaters are the sort that use a coil of hot wire or a heat lamp, these can be "tuned" to the infra -red region of the spectrum which then doesn't,t waste heat by warming up the air. These are particularly good where due to rapid air movement, convected heat would be lost. for instance out doors or in very large rooms.

Answer 3

infrared is EM radiation with wavelengths just above that of visible light and of lower frequencies. The frequencies of infrared are such that they cause oscillation of the molecules of an object when absorbed. This oscillation causes a heating effect.

Answer 4

Absorbing any form of energy causes heating.
Infrared radiation is a form of energy.
Q.E.D.