11BHAI YEH YAHAN KA HIT QUES HAI
IT WAS IN THE FULL TEST 1
AND ALSO IN 1 OF THE TESTS IN THE PHYSICS DEPARTMENT (par maine donno bar galat kar diya )[17][17][17]
THE SOLUTION FOLLOWS
path difference Δx=CO+OP+λ/2(due to reflection)
=OP sin(90-2θ)+OP+λ/2=dsecθcos2θ+d secθ+λ/2=d secθ(1+cos2θ)+λ/2
=2dcosθ+λ/2
for maxima Δx=nλ=2dcosθ+λ/2
2dcosθ=(2n-1)λ/2
cosθ=(2n-1)λ/4d=λ/4d (for n=1)
