A ray of light, incident on the face AB of a prism (made from a material of refractive index μ ) gets refracted there and falls on its other face AC. If it were to go grazing along this face, the angle of refraction (< r), at the face AB, would equal
(1) (A + sin-1 1/μ) as well as sin-1 [sin {cos-1(sin (A+D))}]
(2) (A + sin-1 1/μ) as well as sin-1 [cos {sin-1(cos (A+D))}]
(3) (A - sin-1 1/μ) as well as sin-1 [cos {sin-1(cos (A+D))}]
(4) (A - sin-1 1/μ) as well as sin-1 [sin {cos-1(sin (A+D))}]