Question
Physics Question on Spherical Mirrors
The refracting angle of prism is A and refractive index of material of prism is cot2A The angle of minimum deviation is
A
180∘−3A
B
180∘+2A
C
90∘−A
D
180∘−2A
Answer
180∘−2A
Explanation
Solution
n=sin(2A)sin(2A+dm)
⇒cot(2A)=sin(2A)sin(2A+dm)
⇒sin(2A)cos(2A)=sin(2A)sin(2A+dm)
⇒sin(90−2A)=sin(2A+dm)
⇒90−2A=2A+dm
⇒180−2A=dm