We know for minimum deviation, i1=A+δm2( δm : angle of minimum deviation)
Given δm=A
Hence i1=A
Now, for minimum deviation condition r1=A/2
Hence r1=i1/2
Correct
Option B
μ=sin(i1)sin(r1)
μ=sin(A+δm2)Sin (A/2)
μ=sin Asin A/2 = 2 cos A/2
Incorrect
Option C
Emergence = 90o
sin r2=μ
r2=Sin−1 μ
Also r1=A−r2
sini1=μsinr1
sini1=μsin(A−r2)
sini1=μ(sinA cosr2−cos A sinr2)
But μ sinr2=1
sin i1=μ sinA cosr2−cosA= sinA√4cos2A/2−1−cosA
Correct