Light is an electromagnetic radiation and represents a part of the electromagnetic spectrum (400 to 700 nm). The word usually refers to visible light, because it is visible to the human eye. Continue to read to learn more about light energy.
What is Light Energy
Light is an electromagnetic radiation and represents a part of the electromagnetic spectrum (≈ 400 to 700 nm). The word usually refers to visible light, because it is visible to the human eye. The wavelengths of visible light usually range from 400 to 700 nm, between the infrared (with longer wavelengths) and the ultraviolet (with shorter wavelengths). Visible light is also called photosynthetically Active Radiation (PAR) because photosynthetic organisms perform photosynthesis in this region of the electromagnetic spectrum.
Ultraviolet (UV) is an electromagnetic radiation with a wavelength from 10 nm to 400 nm shorter than that of visible light but longer than X-rays. Depending upon the wavelength, three major ranges in UV radiation are UV-C (100 to 280 nm), UV-B (280 to 320 nm) ant UV-A (320 to 400 nm).
Figure 1: Light Energy
The main source of light on the Earth is the Sun. The amount and duration of solar radiation intercepted at any point on the Earth’s surface varies markedly with latitude. Two factors influence this variation: First, except at the equator, daylight hours are longest during the summer and shortest in the winter.
Second, at higher latitudes radiation hits the Earth’s surface at smaller angle, spreading sun-light over a larger area. In addition radiation that penetrates the atmosphere at a lower angle must travel through a deeper layer of air. In this process, it encounters more particles in the atmosphere, which reflect more of it back into space i.e. making that sunlight much less in-tense. The intensity of light is also affected by altitude. As elevation increases, light intensity also increases because the thinner atmosphere absorbs and disperses less light.
Figure 2: The angle of incoming solar radiation differs at different latitudes, hence, the intensity of incoming solar radiation varies with latitude. In polar areas (i.e. higher latitudes), the sunlight strikes the Earth at a lower angle and spread over a larger surface area, hence, deliver less energy. In tropical locations (i.e. lower latitudes), the sunlight strikes the Earth at a higher angle and concentrated over a smaller area, hence, deliver more energy.
FAQs on Light Energy
The main source of light on the Earth is the Sun.
The sunlight is converted by producers into chemical energy or food. When consumers eat producers, they receive a portion of this energy. When consumed, they also impart a portion of their energy to subsequent users. Thus, energy is transferred from one living creature to another.
Wildlife may have their vital behaviours altered by light. Because of this, endangered species may never fully recover, and it might hinder their capacity to migrate long distances, as well as decrease their reproductive success and overall odds of survival.