Refraction Of Light: Definition, Laws, Applications And FAQs

What Is Refraction Of Light? 

• Refraction of light is the phenomenon of bending of light that travels from one transparent medium to another. 
• Lights travel at different speeds in different media. This is the reason why the bending of light occurs. 

Laws Of Refraction

There are three main laws of refraction: 

1. The First Law Of Refraction

• The first law of refraction states that the incident rays, refracted rays, and the normal to the interface at the point of incidence, all lie in the same plane. 
• The ratio of the sine of the angle of incidence (θi) to the sine of the angle of refraction (θr) is a constant, known as the refractive index (n) of the second medium relative to the first medium.  
• The equation can be expressed as follows: n₁ sin(θi) = n₂ sin(θr). 

2. The Second Law Of Refraction (Snell’s Law)

• The second law states that when a ray of light passes through a rarer medium to a denser medium, the refracted ray comes closer to the normal. 
• Conversely, the refracted ray moves from the normal when the light travels from a denser medium to a rarer one. 
• This law of refraction is termed Snell’s Law. 
• According to Snell’s Law, the ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant.
• The equation can be expressed as follows:
• sin i/sin r = constant 
• This constant or refractive index is denoted by ‘n’. 

3. Third Law Of Refraction

• According to the third law, the incident ray passing through the normal always goes straight into the media after refraction. 

Applications Of Refraction Of Light In Daily Life

• The peepholes in the doors, magnifying glasses, cameras and lenses are used to correct the refractive errors of the human eyes. 
• Spectacles worn by people with defective vision use the principle of refraction. 
• Rainbows are filmed when sunlight is refracted and reflected by water droplets in the atmosphere. 

FAQ’s

1. What causes the refraction of light? 

Refraction of light is caused by the change of speed in light as it travels from one medium to another. 

2. How can you predict the direction of refraction?

Well, you can use the second law of refraction which is Snell’s law to predict the refraction of light. 

Other Related Links

Newton’s Laws Of Motion: Definition, Formula, Applications And Examples