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Light is defined as a form of electromagnetic radiation emitted by hot objects like lasers, led lights or the sun. Light is basically any form of radiant energy and is usually manifest as visible radiant energy. Thus, it is a form of kinetic energy with the ability to make different types of light visible to human eyes. The sun emits a large amount of electromagnetic radiation. We are able to see only a fraction of this energy which is known as ‘visible light’. Solar energy travels in waves. Scientists measure the energy of a wave by calculating its wavelength. This is done by calculating the distance between consecutive points of a wave (measured from a wave’s crest to crest and trough to trough). Where, the difference between wavelengths points to the amount of energy that is carried by them.

Scientists measure the energy of a wave by calculating its wavelength. We calculate the distance between consecutive points of a wave


Visible light constitutes only one among many kinds of electromagnetic radiation emitted by the sun. The electromagnetic spectrum is defined as the range of all possible frequencies of radiation. It consists of different types of electromagnetic radiation rising from the sun including ultraviolet rays and X-rays. Various kinds of radiation and energy from the sun have been differentiated and classified within the electromagnetic spectrum.

Light contains photons which are nothing but minute packets of energy. When an object’s atoms heat up, it results in the production of photons. The electrons gain momentum from the heat and it results in the release of extra energy. Thus, Energy is released in the form of a photon and more photons get produces when the given substance gets hotter in temperature.

Light waves and their source

When it travels, Light takes the form of waves. However, no matter is essential to carry the energy along to travel. This is the reason why light can travel through space where there is no air. This is not the case with sound waves since they have to travel through solids, liquids or gas. This energy is very quick and travels faster than anything. The light speed is equal to 186,282 miles per second. This can be anywhere between 380 nm and 750 nm (a nm unit is measured as one billionth of a meter). Light is a form of electromagnetic radiation. This denotes that it has electric fields and magnetic fields vibrating back and forth very speedily as a wave. Because of the dynamics of quantum mechanics, light is constituted of minute particles having no mass, called photons.

The speed of Light is the fastest in the universe. Light is bent (refracted) with various types of lenses for a number of purposes. For example, it is used in eyeglasses, microscopes, telescopes etc.

As Light is a form of energy, its photovoltaic cells harness the primary energy flow of sunlight to make electricity.

Applications of Light Energy

As we know, Light energy is a form of electromagnetic radiation that can be perceived with naked eyes. Besides bestowing visibility and vision, it is also used for many commercial and scientific purposes. Some applications of Light energy are listed below.


Light is the only source of food generation on the planet. Every organism is dependent on light for their energy and food except for a few chemotrophic organisms such as bacteria.


Organisms including human beings are able to view the objects around them due to the presence of vision. Vision is nothing but refraction of Light. The eyes perceive the image when light falls on an object and the resultant image is sent as a signal to the brain. Thus, light is the only source of vision everywhere.


The whole world is perceived as having color due to the presence of Light. It is Light energy that consists of many spectra and every spectrum has an individual color which is broadly specified as VIBGYOR.