Light Energy - Definition, Uses, FAQs

In this article, we will learn about what is light, how light is produced, what is light energy, what is light actually in physics, whether light is a form of energy, what is antonyms word for light, examples for light energy, interesting facts about light, as per recent understanding what light consists of, images of light.

Introduction of light

Light is nothing but electromagnetic radiation in which only the visible range of wavelength of electromagnetic radiation is visible to the human being. The instrument to measure the intensity of visible light is the photometer. Light is mentioned before as an electromagnetic wave which contains electric waves and magnetic waves which are perpendicular to each other, and the particle called photons which is a minute particle. Hence the speed of light is given by equation as

∁=λv

Where c is the speed of light, λ is the wavelength of light and v is the frequency of light. The electromagnetic spectrum has many waves like

• Radio waves 10³m

• Microwaves 10^-2m

• Infrared 10^-5m

• Visible light 10^-6m

• Ultraviolet waves 10-8m

• X-ray 10^-10m

• Gamma waves 10^-12m

So the visible light is in the range of 10^-6m. Light or visible light waves consist of photons that have no mass, the smallest quantity that can be transported. The light travels at a speed of 3×10⁸m/s. The light from the sun’s surface takes 8 minutes 17 seconds to reach the earth surface. The interesting fact about light is that we human beings can’t travel at the speed of light, because only no mass particles like photons can travel at light speed. We can’t accelerate any object to travel at light speed, because it takes infinite energy to accelerate the objects. No matter is required to carry a light hence it can travel in space where no air is present. Unlike sound energy, it can travel only through objects like solid, liquid. So only sound can’t be heard in space.

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VIBGYOR

In the visible range of light waves of 10^-6m, the human eye can see the colours only in the 400nm to 700nm range. The colours are violet, indigo, blue, green, yellow, orange, red. White light is the composition of seven different colours with a specific wavelength.

Below is the wavelength of white light.

Violet 400 nm to 440 nm

Indigo 440 nm to 460nm

Blue 460 nm to 500 nm

Green 500 nm to 570 nm

Yellow 570 nm to 590 nm

Orange 590 nm to 620 nm

Red 620 nm to 720 nm

The source of light in our day to day life is sunlight. The word related to light is photons stream, packets of energy, flash. The antonyms for light are dark, glare, dull, cloudy.

Uses of light

• photosynthesis-food production by plants by using light

• vitamin D - which is the essential vitamin for human being growth and skin complexion

• vision – without light no one can see the world.

• Temperature- light is a form of energy. Sunlight, which is the source of light, maintains the world temperature by which proper photosynthesis happens, weather and climatic conditions are maintained.

• Sterilising agent- Ultraviolet rays kill microbes and keep things clean and sterile.

• Solar energy- Light which is a form of solar energy is renewable energy. The electricity is produced from the solar panels which are inclined with an angle in sunlight by which PV cells are used to produce direct current.

• Refraction – sunglasses, telescope, lens.

• By using light we can also study the properties of matter. The matter is composed of atoms which are the smallest particles. Atoms have protons, electrons, neutrons. Hence when the light intersects in the matter it gets altered because of the properties of matter. By studying the altered light we can learn about the material properties.

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Definition for Light energy

Light energy is a form of kinetic energy which can be transmitted without mass, as it is composed of minute particles called photons that have no mass. Sunlight emits sun rays which have electromagnetic rays in which only the visible range of wavelength of light is visible to the human eye. Now we can know how objects are getting to our eyes during sunshine. We can see any object because light from the sun falls on the object, and it moves in space and gets reflected in our eyes. When the light reaches our eyes, the signals will be sent to the brain. The brain will derive the information from the signals that detect the object size, shape, presence. This signal transmission will happen in seconds.

Commercial uses of conversion of light energy

• The conversion of light energy to chemical energy called photosynthesis is used by plants to prepare chlorophyll. When the photons from sunlight bombard an electron in the chloroplast, those electrons will get excited which has arisen in the energy levels. Chlorophyll absorbs only red light and green light from the white light and it reflects the green light to us. So only the colour of plants appears green to us.

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Another commercial use of light energy is solar energy. Sunlight is the main source of power. Photovoltaic cells are used to convert sunlight to electricity. In simple words, solar energy uses the heat and light from the sun and converts that into direct current. When the sun rays strike the panel energy from the sun is absorbed through the PV panels. This creates the flow of current in the panels which lights up the whole house. These solar panels when they are installed in each house we can afford our own electricity demand. Unlike any energy like thermal energy, nuclear energy this solar energy is free of pollution, maintenance-free, and renewable energy as it is available all over the year.

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