Understanding of Refraction of Light

Refraction of Light

Refraction is the bending of a wave when it enters a medium where it's speed is different. The refraction of light when it passes from fast medium to a slow medium bends the light ray toward the normal to the boundary between the two medium. The amount of bending depends on the indices of refraction of the two medium is described quantitatively by Snell's Law

Remember that angles of incidence and refraction are measured from the normal, which is an imaginary line perpendicular to the surface.



Definition: Snell’s Law
n₁sin θ₁ = n₂ sin θ₂
where
n₁ = Refractive index of material 1(Air)
n₂ = Refractive index of material 2(Water or Glass)
θ₁ = Angle of incidence
θ₂ = Angle of refraction

light going from air into water or glass

light going from water or glass into air

angle of incidence of 0 degrees, no bending occur

Phenomenon of Refraction of Light

Light Pillar

Fire Rainbow

Fire Rainbow

upside-down rainbow

Understanding of Reflection of Light

Law of Reflection

The First Law : The angle of incidence is equal to the angle of reflection. 

The Second Law : The incident ray, the normal and the reflected ray all lie in the same plane. 

If the reflecting surface is very smooth, the reflection of light that occurs is called specular or regular reflection. the laws of reflection are as follows:

1.  The incident ray, the reflected ray and the normal of the reflection surface at the point of the incidence lie in the same place.
2. The angle which the incident ray makes with the normal is equal to the angle which the reflected ray makes to the same normal.
3. The reflected ray and the incident ray are on the opposite sides of the normal.

☆ Did you notice that☆

         i. the size of the image is the same as you (object)

        ii. the distance of the image seem as the same distance of you from the mirror. 

        iii. when you move your left hand, the image will move it right hand
        iv. then you image never upside down .

   Reflection of mirror

  Specular Reflection

Specular Reflection

The angle of incident equals the angle of reflection

θ_i = θ_r

Application of Light Reflection

Reflectors of the Bicycle

Concave and Convex Lens

Total Internal Reflection of Diamond

Total Internal Reflection of Fiber Optics

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