Light energy


Also called light and/or luminous energy; refers to the energy that is transported through light waves. Light is made up of light waves, a type of electromagnetic wave that is emitted by hot objects such as lamps or the sun. In turn, these waves are made up of photons, which are small packets of energy.

The lumen is the unit of study of energy that determines the over time, as well as the variable sensitivity of the eye to light waves. The energy of light moves through waves and at the speed of light, so it cannot be stored.

The sun is the main source of light that exists and transmits a significant amount of capable of sustaining the development of life on planet Earth. However, there are other sources of light energy, such as fire or lasers.

The electromagnetic waves emitted by the energy are detected by the direction of the visit; however, there are ultraviolet waves, which are not visible and also transmit energy, but which are harmful to the health of living beings.

Light energy

Examples of light energy

The energy of light is present in many of the activities that people carry out daily, for example, when we turn on the television to watch a particular program, we can do so thanks to the light waves transmitted by the device, which are perceived by the eye and give us an image. As in this example, there are many others.

  1. The energy generated by lamps is the result of the transformation of electrical energy into light energy, which is used to illuminate dark or poorly lit spaces.
  2. The energy emitted by the sun is used by plants and transformed into chemical energy to carry out the photosynthesis process.
  3. A lit candle generates light through a flame of fire with which a dark space can be illuminated.
  4. A light bulb transmits light through a process of electrical energy, which in turn produces thermal energy, generating heat.
  5. Flashlights that use batteries also transmit light energy through a chemical process that generates electricity and light.


There are two types of light energy


It is that which is transmitted by the sun.


It is generated by the use or application of other energies, for example, electrical energy, through which lamps can generate light energy.


  1. The light energy that comes from the sun is free and its source of energy is inexhaustible.
  2. The light energy that comes from the sun is not polluting.
  3. Several techniques have been generated to produce electrical energy through the light energy generated by sunlight.
  4. Plant and animal life on Earth occurs in large percentages thanks to the positive effects that the light energy of the sun generates in the life cycle.

Through light energy, various activities of daily life can be carried out through the use of various devices that generate light in the dark or transmit images or content such as computers or mobile phones.


  1. To harness the generated by the sun on a large scale, it is necessary to invest large amounts of money to make solar panels that absorb solar energy.
  2. Large tracts of land must be used to place solar panels.
  3. Solar radiation varies according to the seasons.
  4. Depending on the geographical location of a place, more or less an amount of light energy can be obtained through the rays of the sun.
  5. The energy of artificial light depends on other energy sources, such as electricity.

Sources for obtaining

There are different sources of energy that can interact with each other to generate light.

Renewable energy sources, such as solar, hydroelectric, wind, geothermal, and biomass energy, are capable of producing light energy as their energy capacities are applied and transformed. However, the application of these energy sources still has high economic costs, so, although they are used more every day, not everyone can afford to use these energy sources.

On the other hand, non-renewable energy sources that can generate light energy cover the largest percentage of human energy demand, and their application is cheaper than renewable energy sources. However, these energy sources are polluting and directly affect the quality of life of all living beings. These energies are derived from coal, gas, oil, and uranium.



Refraction refers to the change in the movement of light when the medium in which it moves changes. The energy of light can move through different media, such as air, water, and even a vacuum, varying its speed in each of these media. This property can be observed through the human eye and explains many everyday phenomena, such as the flickering of stars. In the universe, light travels in a vacuum, so when it enters Earth’s atmosphere, it changes the averages. In this change, the light waves change speed and refract, thus producing the observed flicker of the earth.


Reflection refers to the change in direction of light waves when they collide with an object and bounce back. This property is very important because thanks to the reflection of light it is possible to observe those objects that do not have their own light. This property can be checked daily, for example by turning off the lamp in a room. All objects are no longer visible because light stops reflecting off them.


Diffraction refers to the change of direction of light waves when they meet an obstacle or when they pass through a slit. They also occur in sound waves or fluids. This property applies to the operation of camera lenses. Light waves enter through a small hole and the diffraction property causes them to propagate within the camera.


Interference occurs when two or more waves coincide and their effects add up. These effects can be constructive or destructive depending on where they are in the wave. Constructive interference occurs when light waves are at the points where the two crests meet, so the wave frequencies add up. On the other hand, destructive interference occurs when a valley meets a ridge. In this case, the amplitudes are subtracted and can disappear completely.


According to the developments of the different processes (natural and artificial), light energy uses its fundamental role as follows:


Photosynthesis is one of the most important functions that energy performs in nature. In this process, plants transform the sun’s energy into food for plants and, in turn, produce the oxygen that gives life to other living things. On the other hand, light is an important source of vitamins for humans. Thanks to the energy of light, photobiogenesis occur, a process in which vitamin D is generated, necessary for the development of human bones.


Living organisms can see objects around them thanks to their eyes, but the eyes work thanks to light. Light waves stimulate the eyes to perceive images when light hits them and the information is sent to the brain. Therefore, the energy of light is fundamental in the vision of the human being and of all living animals.


The colors perceived by the eyes are also possible thanks to the. Light is made of different spectra and each of them can be perceived through a different color. The mixture of all the colors of the spectrum produces white light, and in turn, white light is divided into all the colors of the spectrum through the phenomenon of scattering. This is a phenomenon that can be observed daily in the rainbow. This occurs when white light is scattered through small water droplets present in the air after the rain.

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