Question 66. Thank you.

Dear student,
i + e = A+ d
i --->angle of incidence
e--->emergence
A--->angle of prism
d---->angle of deviation
Now
i=e= (3/4)A (
》3/4)A+(3/4)A=A+d
》1.5 A-A=d
》d=A/2
now
 A=60 degree (for equilateral prism)
So
d=30 degree.

Regards.