Question

20. In the following figure angle 1 point
of deviation is represented by *
23
B
Ос
D
O E​

Answer 1

Answer:

Angle of deviation δ is given by δ=i+e−A

i and e are interchangeable due to reversibility of light. At a value of i=e, we get minimum deviation, and the deviation increases for both larger and lesser values of i. Therefore δ first decreases with increase in i, reaches a minimum and then increases.