Light Energy – Definition, Sources of Light
Light energy
Key Concepts
- What is light energy?
- Sources of light
- Mediums of propagation of light
- Formation of shadows
Explanation
Definition:
Light is a form of energy that travels in a straight line. Light is a mechanical wave and can travel through a vacuum.
Important points of light energy:
- Light is the form of energy.
- Light can travel through a vacuum.
- Light can travel at the speed of 3 x 108 m/s.
- Light has energy particles called photons.
- Light is the major component that humans have a vision.
Sources of light:
There are two sources of light energy:
- Natural sources of light
- Artificial sources of light
Natural sources of light:
The light which exists naturally and is not artificial is called the natural source of light. The natural sources of light are:
- Sun
- Stars
- Thunder
Artificial sources of light:
The light which is created by man and does not exist naturally is called the artificial source of light. The artificial sources of light are:
- Electric bulb
- Candle
- LED
Mediums of propagation:
There are three mediums of propagation of light, they are:
- Transparent medium
- Translucent medium
- Opaque medium
Transparent medium:
The medium through which light can pass completely is called transparent medium.
Examples:
- Water
- Glass
Translucent medium:
The medium through which light can pass partially is called transparent medium.
Examples:
- Butter paper
- Soap water
Opaque medium:
The medium through which light cannot pass is called transparent medium
Examples:
- Mirror
- Stone
Formation of shadow:
Shadows are formed when the opaque medium stops the path of the light ray.
Shadows are dark, and they take the shape of the outmost structure of the opaque object.
Parts of shadows:
Umbra:
Umbra is the darkest region of the shadow, which is present in the central region of the shadow.
Penumbra:
The penumbra is not so much a dark region at the outermost part other than the central region.
Summary:
Definition:
Light is a form of energy that travels in a straight line. Light is a mechanical wave and can travel through a vacuum.
Important points of light energy:
- Light is the form of energy.
- Light can travel through the vacuum.
- Light can travel at the speed of 3 x 108 m/s.
- Light has energy particles called photons.
- Light is the major component that humans have the vision.
Sources of light:
There are two sources of light energy:
- Natural sources of light
- Artificial sources of light
Mediums of propagation:
There are three mediums of propagation of light, they are:
- Transparent medium
- Translucent medium
- Opaque medium
Parts of Shadows:
Umbra:
Umbra is the darkest region of the shadow, which is present in the central region of the shadow.
Penumbra:
The penumbra is not so much a dark region at the outermost part other than the central region.
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