Question

Calculate the angle of deviation for angle of
Incidence 45° when the ray passes through
om equilateral prism such that angle of
incidence is equal to angle of emergence.​

Answer 1

Answer:

Given: A ray of light passes through an equilateral prism such that angle of incidence is equal of emergence and the later is equal to (  

4

3

​  

)  

th

 of the angle of prism.  

To find the angle of deviation.  

Solution:

If angle of incidence be i,  angle of emergence be e and angle of prism be A.

According to the given criteria,

i=e=  

4

3

​  

A.......(i)

Angle of deviation for the light in prism is,

δ=i+e−A

⟹δ=2i−A (as given i=e)

⟹δ=2(  

4

3

​  

A)−A (from eqn(i))

⟹δ=  

2

3−2

​  

A=  

2

1

​  

A

As the prism is an equilateral triangle, all the angles of the prism is equal to  

60  

∘

 each, i.e., A=60  

∘

 

δ=  

2

1

​  

×60=30  

∘

 

is the angle of deviation.

Explanation: