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2. Solar Energy
There are two alternative theories of how radiation and light travel: wave theory and photon theory
According to wave theory, radiation and light are regarded as a travelling wave created by an oscillating electric field. According to photon theory, radiation is regarded as a stream of small packages of energy (known as photons). The behaviour of radiation (light) as particles and waves is known as "wave-particle duality".
The wavelength, usually given the symbol lambda, is the distance taken for the wave pattern to repeat itself e.g. distance from crest to crest or trough to trough. Any fixed point on the wave moves at velocity 'c (3 x 108 m/s)' in the direction of the light beam.
According to photon theory, radiation is regarded as a stream of small packages of energy (known as photons).
There are situations where the behaviour of light can be explained only by wave theory, but in other circumstances only photon theory provides a means of explaining the phenomena, notably those which are of concern for the environment. Even then, wave theory provides the basic parameters (wavelength and velocity) which are conventionally used to describe radiation quantitatively.
Can you describe wave theory and photon theory?