(ii) Find out the angle of minimum deviation for equilateral prism if angle of
incidence and emergence is 48degree
Answers
Answer:
The emergence angle is 48°.
(I). The angle of deviation will be less than 36°.
(II). The angle of deviation will be more than 36°.
Explanation:
Given that,
Incident angle = 48°
Deviation angle = 36°
Prism is equilateral.
So, angle is 60°
We need to calculate the angle of emergence
Using formula of emergence angle
\delta=(i_{1}+i_{2})-Aδ=(i
1
+i
2
)−A
Where, i_{1}i
1
= incidence angle
\deltaδ = deviation angle
Put the value into the formula
36=48+i_{2}-6036=48+i
2
−60
i_{2}=48^{\circ}i
2
=48
∘
The emergence angle is 48°.
(b). If the angle of incidence is changed
(I). Incidence angle is 30°
We need to deviation angle
Using formula of deviation
\delta=i_{1}+i_{2}-Aδ=i
1
+i
2
−A
Put the value into the formula
\delta=30+48-60δ=30+48−60
\delta=18^{\circ}δ=18
∘
The angle of deviation will be less than 36°.
(II). Incidence angle is 60°
We need to deviation angle
Using formula of deviation
\delta=i_{1}+i_{2}-Aδ=i
1
+i
2
−A
Put the value into the formula
\delta=60+48-60δ=60+48−60
\delta=48^{\circ}δ=48
∘
The angle of deviation will be more than 36°.
Hence, The emergence angle is 48°.
(I). The angle of deviation will be less than 36°.
(II). The angle of deviation will be more than 36°.