Question

Do it i will mark brainlist...

Answer 1

let angle of reflection r=1/2i

r/I= 1/2
from snell's law
sin I/sinr=1
I =2r
sin2r/sinr =1
solve this
sin(r+r) /sinr =1
sin rcosr+cosrsinr/sinr=1
2cosr=1
cosr=1/2
but from above question
r=cos—1 (Ù/2) ù- mu