# Can you ever have a situation in which a light ray goes undeviated through a prism ?

509 Points
13 years ago

in case of right angled isoceles prism if  a light is incident at the face AB ( prism is right angled at c) then it comes out parallel to the incident ray.....

420 Points
13 years ago

Dear Nikhil

there are two cases

1. refractive index for the prism and external medium is same
2. deviation= 2 x incidence angle - prism angle,  for deviation to be zero incidence angle = prism angle/2

All the best

AKASH GOYAL

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Pulkit Singhania
19 Points
6 years ago
But Deviation = 2i - angle of prism is only valid for some prisms.As when I = e angle of incidence = angle of emergence then deviation = (I+e)-angle of prism so deviation = 2i - angle of prism.Maybe when I = angle of prism/2 then I = e does not holds
Sakshi Rathore
21 Points
6 years ago
The only way Ray can pass through it undeviated if angle of incidence is zero i.e. incident Ray is perpendicular to the surface but In a prism the light Ray has to pass through two interface at an angle with each other.It can`t be perpendicular to both