Laws of refraction
a) Incident ray, refracted ray and normal at the point of incidence lie in the same plane.
b) Ratio of sine of incidence and sine of refraction is constant for the given color and pair of media.
ABCD is a glass slab. EF is incident ray which is incident on point 0 on air-glass interface.
- NO is normal and _LEON = :I; which Is angle of incidence.
- NV is normal extended towards the glass slab and .LV '00 = Zri; which is angle of refraction.
- 00' is refracted ray from surface AB. It behaves like Incident ray on surface CD.
- The ray EF bends when it enters the slab to become 00'.
- MO' and O'M' are normal on surface CD.
- GH is the emergent ray. • ZOO' Al = Li,; which is angle of Incidence at surface CD.
- Z.110' H = Zr,; which Is angle of refraction at surface CD.
- It is observed that EF. NO and 00' lie in the same plane: which is in accordance to the first law of refraction.
- It is also observed that EF II GH; which means emergent ray is parallel to incident ray.
This happens because the degree of bend at opposite surfaces of glass slab is same.
