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Light Energy – Definition, Sources of Light

Aug 19, 2022
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Light energy

 Key Concepts

  • What is light energy?
  • Sources of light
  • Mediums of propagation of light
  • Formation of shadows

 

biosphereExplanation

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: 

  1. Light is the form of energy. 
  1. Light can travel through a vacuum. 
  1. Light can travel at the speed of 3 x 108 m/s. 
  1. Light has energy particles called photons. 
  1. Light is the major component that humans have a vision. 

Sources of light: 

There are two sources of light energy:  

  1. Natural sources of light 
  1. 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: 

  1. Sun 
  1. Stars  
  1. 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: 

  1. Electric bulb 
  1. Candle 
  1. LED 

Mediums of propagation:  

There are three mediums of propagation of light, they are:  

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  1. Transparent medium 
  1. Translucent medium 
  1. Opaque medium 

Transparent medium: 

The medium through which light can pass completely is called transparent medium. 

Examples: 

  1. Water 
  1. Glass 

Translucent medium: 

The medium through which light can pass partially is called transparent medium. 

Examples: 

  1. Butter paper 
  1. Soap water 

Opaque medium: 

The medium through which light cannot pass is called transparent medium 

Examples: 

  1. Mirror 
  1. 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. 

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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: 

  1. Light is the form of energy. 
  1. Light can travel through the vacuum. 
  1. Light can travel at the speed of 3 x 108 m/s. 
  1. Light has energy particles called photons. 
  1. Light is the major component that humans have the vision. 

Sources of light: 

There are two sources of light energy:  

  1. Natural sources of light 
  1. Artificial sources of light 

Mediums of propagation: 

There are three mediums of propagation of light, they are:  

  1. Transparent medium 
  1. Translucent medium 
  1. 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. 

Comments:

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