Light energy is present in electromagnetic radiation with a wavelength between 380 and 750 nanometers.
Light energy is that generated and transferred by light waves. It is considered a form of electromagnetic energy , a concept that refers to all the waves of magnetic and electric fields that are transmitted through space.
Before moving forward with the definition, it is necessary to indicate that energy is the ability to carry out a task or transformation. The concept is generally linked to the natural resource that harbors that potential and to the means that make its extraction and use possible.
Luminous , meanwhile, is an adjective that refers to what is related to light . Physics calls light the electromagnetic wave that is in the visible spectrum : that is, it is located in the area of the electromagnetic spectrum that humans can perceive through sight.
Composition of light energy
Electromagnetic radiation in general and light specifically are made up of elementary particles called photons . These photons carry energy.
Light energy is the energy carried by photons of visible light . It is important not to confuse it with radiant energy , which includes other types of electromagnetic waves that the human eye cannot perceive (such as ultraviolet light or infrared light).
The manifestation of light energy on matter can occur in different ways. It is measured in lumens per second and its symbol is Qv .
It can be said that light energy is linked to the luminous flux existing in a certain period. The idea of luminous flux, meanwhile, refers to the measurement of the luminous power that is perceived. It must be differentiated from radiant flux , which includes all the emitted power, including those wavelengths that the human eye cannot perceive.
Photovoltaic conversion allows the sun's light energy to be transformed into electrical energy .
Absorption and reflection
When light energy interacts with an object, the characteristics of that interaction depend on the chemical and physical properties of the element that is illuminated and the geometric arrangement with which the light reaches it.
In this way, there are bodies that have the ability to absorb light energy , while other objects partially reflect it. Depending on one faculty or another, light energy can be used in different ways.
Take the case of a photovoltaic cell , also known as a photoelectric cell , solar cell , solar cell or photocell . These devices are built with materials that can absorb photons and, in turn, emit electrons. The capture of these electrons produces an electric current that can be used as electricity .
It is possible to affirm, therefore, that solar or photovoltaic cells – which are usually grouped into solar panels – manage to convert light energy into electrical energy. This light energy has the sun as its energy source ; In this framework, it cannot fail to be noted that the total electromagnetic radiation of the sun generates what is known as solar energy .
The interior lighting and exterior lighting of a home are possible thanks to the use of light energy.
Light energy and solar energy
The solar energy present in sunlight includes both visible spectrum light as well as infrared (IR) and ultraviolet (UV) rays . Therefore, solar energy has light energy, but also other kinds.
In total, about 174,000 terawatts of solar radiation reach planet Earth every day. It is estimated that about 30% of that insolation is reflected and returns to space.
It is important to keep in mind that solar energy is renewable energy : it is inexhaustible. While the sun's light energy is used directly and daily, its conversion into electrical energy makes lighting possible through streetlights, lamps and bulbs, for example.
Photometry
Photometry is the scientific discipline dedicated to the measurement of light . This field of knowledge, therefore, examines how electromagnetic radiation stimulates human vision. Light energy, therefore, is considered as a photometric quantity.
Vision is a sense that is based on the functioning of the eye , the organ that receives light and proceeds to transform it into electrical signals to transmit them to the brain. The region of the eye called the retina is where light energy is converted into nerve impulses that are sent to the brain for processing. Rods and cones are specialized cells in the retina that are sensitive to light waves.
Vision disorders occur due to an injury or deficiency in one of the structures involved in the process. When the person is not able to see, they suffer from blindness .
It is interesting to note that photometry distinguishes between illuminance (the level of luminous flux that affects a certain surface per unit area) and luminous emittance (the level of luminous flux emitted by a surface per unit area). The device that measures illuminance is known as a luxmeter .