Light Sources - Natural Light Sources, Artificial Light Sources, FAQs
Light is what we use daily. It helps us see things around us and keeps our surroundings bright. Plants also use light to grow and prepare food. Light can also be natural or man-made. The Sun, stars, and fireflies are examples of natural light sources. Bulbs, candles, and tube lights are examples of artificial light sources. A natural light source is one found in nature. Artificial light sources are made by people and need energy to work. This article talks about both types of light sources and some simple questions related to them.
This Story also Contains
- What is Light?
- Types of Light Source
- Difference Between Natural and Artificial Light Sources
- Fun Facts About Light
What is Light?
Light is a form of energy that allows us to see. Light moves in a straight line and can travel through air, water, and empty space. In the absence of light, everything would be dark, and our eyes would not be able to perceive it. The Sun is the main natural source of light. Light enables us to see colour, shape, and objects near us. It also helps the plants prepare their food through the process of photosynthesis.
Commonly Asked Questions
The aurora borealis, or Northern Lights, is a natural light display in Earth's sky. It occurs when charged particles from the sun collide with atoms and molecules in Earth's atmosphere. These collisions excite the atoms, causing them to release energy in the form of colorful light.
The ozone layer in Earth's stratosphere absorbs much of the sun's ultraviolet (UV) radiation, particularly UVB rays. This natural "filter" significantly reduces the amount of harmful UV light reaching Earth's surface, protecting life from potential DNA damage. However, it allows visible light and some UVA rays to pass through.
The green flash is a rare optical phenomenon that can occur just as the sun is setting or rising. It happens because Earth's atmosphere acts like a prism, refracting sunlight into its component colors. The blue light is scattered away, leaving the green light visible for a brief moment. This effect is usually only visible under very clear atmospheric conditions and requires an unobstructed view of the horizon.
Blackbody radiation refers to the electromagnetic radiation emitted by an ideal absorber of all wavelengths. As an object's temperature increases, it emits more intense radiation and at shorter wavelengths. This principle explains why heated objects glow, starting from red and progressing to white-hot as temperature increases.
Triboluminescence is the emission of light when a material is mechanically stressed or broken. It occurs in some crystals and even in everyday items like wintergreen Life Savers candies. When you crush these candies in the dark, you can see a brief flash of light. This happens due to the separation and reunification of electrical charges as the crystal structure is broken.
Types of Light Source
Light sources can be grouped into two main types, which are natural and artificial light sources.
Natural Light Sources – Definition and Examples
Natural light sources arise in nature and are not made by human beings. These sources generate light by themselves without any support from electricity or fuels. Natural light is predominantly available during the day, while some sources may be seen at night.
Examples of Natural Light Sources
- Sun – The primary and most powerful source of light on Earth. It gives us daylight and energy.
- Stars – They appear as tiny dots of light in the night sky. They are, in fact, huge spheres of burning gases far away.
- Fire –Natural fire from wood or grass burning also produces some light.
- Lightning – It is a flash in the atmosphere during storms created by an electric discharge.
- Fireflies – The insects that glow through bioluminescence, a natural chemical process.
- Lava – The hot, glowing liquid rock from volcanically active regions can emit light.
- Some sea creatures – Deep-sea creatures like jellyfish can glow in the dark using bioluminescence as well.
Artificial Light Sources – Meaning and Examples
Artificial light sources are man-made. They were developed to bring illumination when natural light is not enogh, particularly at night or dark areas. These source use electricity, chemicals, or fuels to produce light.
Examples of Artificial Light Sources
- Electric bulb – The most common source of light used in homes and schools that works with electricity.
- Tube lights – Long lights to illuminate rooms and halls.
- LEDs – Light-emitting diodes that consume less energy and last for a long time.
- Candle – An ancient way of producing light, burning wax.
- Oil lamp – It burns oil and produces light; it is commonly used in villages.
- Laser lights – A focused beam of light, used in machines, shows, or surgeries.
- Mobile flashlight – A small LED torch attached to mobile phones for emergency work.
Commonly Asked Questions
Natural light sources produce light through natural processes like nuclear fusion or combustion, while artificial light sources are human-made devices that convert other forms of energy into light. For example, the sun is a natural light source, whereas a light bulb is an artificial light source.
Moonlight is not a primary natural light source. The moon itself doesn't produce light; it reflects sunlight. However, it can be considered a secondary natural light source as it provides illumination at night by reflecting the sun's light to Earth.
Incandescence is light emission from a hot object due to its high temperature, like in traditional light bulbs. Luminescence, on the other hand, is light emission that doesn't result from high temperatures but from electronic excitation, such as in LED lights or bioluminescent organisms.
LED (Light Emitting Diode) lights work on the principle of electroluminescence. When an electric current passes through a semiconductor material, electrons move through the material and fall into lower energy levels, releasing energy in the form of light.
Fluorescent lights work by passing an electric current through a gas (usually mercury vapor) to produce ultraviolet light. This ultraviolet light then strikes a phosphor coating on the inside of the tube, causing it to fluoresce and emit visible light.
Difference Between Natural and Artificial Light Sources
Table below is showing the diffrence between nagtural and artificial source of light.
Natural Light Sources | Artificial Light Sources |
| Found in nature | Made by humans |
| Do not need electricity or fuel | Need electricity, fuel, or batteries |
| Examples: Sun, stars, lightning, fireflies | Examples: Bulb, candle, LED, tube light |
| Work on their own (no switch or control) | Can be turned on or off by us |
| Mostly available during the daytime or naturally | Available anytime as per need |
| Cannot be created or controlled by people | Can be created, controlled, and used as needed |
Fun Facts About Light
- It travels at a speed of 300,000 kilometres per second in space.
- Sunlight takes approximately 8 minutes to reach the surface of the Earth.
- The Moon does not emit its own light but only reflects the light coming from the Sun.
- Fireflies and some other sea creatures have the ability to emit light naturally; the property by which this is achieved is called bioluminescence.
- The colours of white light consist of seven distinct colours, which you see in a rainbow.
- Light travels in a straight line unless it is bent by something, such as water or a lens.
- LED lights have a longer life and consume less power as compared to incandescent bulbs.
Frequently Asked Questions (FAQs)
The human eye detects colours using specialised cells called cones in the retina. There are three types of cones, each sensitive to different wavelengths of light:
S-cones (short wavelength): Most sensitive to blue light.
M-cones (medium wavelength): Most sensitive to green light.
L-cones (long wavelength): Most sensitive to red light.
Fireflies produce light through a chemical reaction called bioluminescence. They have a light-producing organ where a chemical called luciferin reacts with oxygen, aided by an enzyme called luciferase. This reaction produces light with very little heat, making it a highly efficient light source.
Holographic displays create 3D images by using the principles of light interference and diffraction. They work by:
Light sources can significantly impact human circadian rhythms:
Quantum mechanics is fundamental to understanding light production at the atomic level. It explains:
These are different measures of light:
Different artificial lights affect plant growth in various ways:
Atmospheric conditions can significantly alter the appearance of natural light:
Fiber optic lighting works on the principle of total internal reflection. Light enters one end of a thin, flexible fiber and is reflected off the inner walls as it travels along the fiber's length. This allows light to be transmitted over long distances with minimal loss, even around bends. In lighting applications, a single light source can illuminate multiple fiber optic strands, creating unique lighting effects.
Photoluminescence and chemiluminescence are two different mechanisms of light production: