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Light Energy – Definition, Sources of Light

Grade 6
Aug 19, 2022
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Light energy

 Key Concepts

 

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:  

parallel
  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. 

parallel

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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