Explain the refraction of light through a triangular glass prism using a labelled ray diagram. Hence define the angle of deviation.
• ABC is prism with base BC
• PE is incident ray on surface AB. It makes < PEN with the normal NE. This angle is angle of incidence.
• After entering the prism, the light ray bends towards normal. In this case, EF is refracted ray. <N' EF is angle of refraction.
• Once the refracted ray emerges from prism into air, it bends away from normal. In this firgure, FS is emergent ray. <SFM is angle of emergence.
Angle of Deviation: The angle between incident ray and emergent ray is called angle of deviation. Here, <SGH is angle of deviation or <D.
