What is radiant energy?

What is radiant energy? The sun transfers its energy or heat to the earth by means of radiation.

There are 3 types of thermal transfer. These are conduction, convection, and radiation.

If the sun could transfer its energy to the earth by means of conduction, it would do it through air.

However, the sun cannot transfer energy ny means of conduction since air is a poor conductor.

Convection does not work either since convection occurs only in fluid such as liquid or gas.

How does the sun's energy reach the earth then? It reaches the earth my means of electromagnetic waves.

Any energy that is tranferred by radiation or electromagnetic waves is called radiant energy.  

Radiant energy includes ultraviolet waves, X rays, gamma rays, radio waves, infrared radiation, and microwaves.


Real life examples of radiation and wavelengths.

Objects at low temperatures produce long waves while objects at high temperature produce short waves.

The wavelength of infrared waves is between the wavelength of radio waves and that of light waves.

You encounter infrared waves in the form of heat daily. Although infrared waves are not visible to the human eye, you will feel them as heat. The heat from a fire place comes to us by radiation in the form of infrared waves.

If an object becomes a little hotter than infrared waves, some of the energy it produces will be in the range of visible light such as the energy coming from a lightbulb.

Radio waves have bigger wavelengths than infrared waves.

The object that produce these waves is not as hot as the object that produces infrared waves.

We cannot feel this kind of wave. However, its presence is clear when you listen to the radio.

The sun and a lightbulb produce both infrared radiation and visible light.


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