Light Sources - Natural Light Sources, Artificial Light Sources, FAQs

In this article we will be studying about types of light, sources of light, natural sources of light, artificial sources of light, light source, what is a light source, artificial light, point source of light, and examples of natural sources of light.

Example of light-Sunlight

What is light made of?

Light exhibits dual nature. It shows properties of both waves and particles.

According to wave theory, light is made up of a bundle of electromagnetic fields that carry a specific amount of energy.

According to particle theory, light is made up of particles called photons.

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Types of Light source

There are many different types of light source but we categorise them as-

• Natural Sources

Examples of natural sources of light or name two natural sources of light- Sun, Stars, etc.

Pictures of natural sources of light

• Artificial Sources

Torch, Candle, Bulb, Lamp, etc. are examples of artificial sources of light.

Now the question arises, what is natural light?

Sources of Light

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What is a Natural Source of light?

Before answering the above question we will talk about what is natural light?

Natural light definition: In simple words, natural light is the light that is generated by a natural source.

The universe is filled with numerous sources of light. The emitted light from a few sources of light reaches the Earth. The following natural light sources emit light:

• The Sun is one of the major sources of light of the earth. Also, the Sun is the main light source for the entire Solar System.
  In the sun, heat and light are produced by the process called Nuclear Fusion.
• Many other stars also produce light, but only a small amount or no amount from them reaches the earth because of the large distance.
• The moon does not have its own light. So, it reflects the light from the Sun and acts as one of the natural light sources on the Earth.
• Bioluminescence - Some living organisms produce light by a chemical reaction that occurs within them.[Another natural light source]
  For Example- Fireflies, jellyfish, glow-worm, some microorganisms and deep-sea plants.
• Volcanic eruptions & Lightning also emit light.

Artificial Light Sources or Man-made Sources of Light

Apart from natural light sources, there are different artificial light sources that emit light. The different artificial light sources can be put the following categories-

• Incandescent Sources:

When certain objects are heated to a high temperature, they begin to emit both infrared and visible light in the process.

Example- Candle, incandescent lamp.

• Luminescent Sources:

By bypassing current (i.e, by accelerating charges in a luminescent material.) Through the material, light can be produced.

Example- Fluorescent tube light, electric bulb

• Gas Discharge Sources:

Light can be produced/created by passing electricity across a certain gas at very low pressure.

Example – Neon lamp, Sodium lamp.

What is a light source?

A light is a form of energy which is produced by a source. So, a light source is a device/optical transmitter that produces energy in a visible range.

What is artificial light?

Artificial light is visible light that is generated by artificial light sources. It also contains some IR and UV radiation, as opposed to natural daylight (most LEDs do not contain IR and UV).

Artificial Lamp

Point source of light

A point source of light is a source of energy in the form of light(or radiation) which is concentrated at a point and considered as having no spatial extension.

Example of point source of light -Sunlight coming in room through a pinhole.

Q. How can you obtain a point source of light?

We can obtain a point source of light by placing the screen with a pinhole in front of the screen.

What of extended source of light?

An extended source of light- The source of light which forms both umbra as well as penumbra region.

For Example- Sun is an extended source of light.

Cold source of light

Cold source is also known as luminescence. It is the source that emits light when things are cold.

Q. Who made electric light?

In 1803, Humphry Davy invented the first electric light.

Q. Why do we need light?

Light is itself a life. Light is a vital component for all living organisms as it is the main source of energy on our planet.

What is Artificial Light?

Artificial light sources are the sources that are developed to compensate for natural sources.

Types of artificial Lighting

There are 5 common types of artificial lighting as follows-

Natural Lighting

Natural Lighting is a technique which efficiently brings natural light into our homes. This technique reduces the artificial light requirements and saves a lot of energy.

Natural light examples- Sun and Moon

1. Incandescent lamp.
2. Compact fluorescent lamp.
3. Fluorescent tube.
4. Discharge lamps.
5. Light Emitting Diode (LED).

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Who is the light

Different types of lamps and their working

Miscellaneous Questions

1. Name the source of electricity in a torch.

Batteries

2. Name the most important source of light for the earth.

The Sun

3. Write the name of sources of light at home?

LED/Bulbs, Lamps, Light from TV & phone’s screen, etc.

4. Examples of sources of light.

The Sun, Bulb, Torch, Stars, etc.

5. What is the primary source of light?

Light comes from the light sources and our main source of light is the Sun.

6. Natural or artificial can be a category of what?

Sources of light.

7. State the examples of natural sources of heat.

The Sun and the stars

8. Incandescent light source examples.

Glow discharge lamps, neon lamps, fluorescent lamps, flood lights, car headlights, etc.

9. Name the types of Illumination.

• Halogen incandescent
• Metal halide lamps & Xenon strobe lamps
• Fluorescent light(high frequency)
• LED Illumination
• Cold light sources such as Metal halide light sources

These are also known as Artificial lighting types.

10. What is artificial white light?

The mixture of three colours only: red, green and blue create the white colour of artificial light (or fluorescent lamps). The non-continuous emissions of various halophosphate or triphosphate give the white colour.

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