Which relation correctly connects real depth

PHYSICS · Single correct · CBSE · Physics · Light — Reflection and Refraction · Light — Reflection and Refraction

Problem

D

, apparent depth

d

and refractive index

n

for an object under water observed from air along the normal? (a)

n = \dfrac{D+d}{d}

(b)

n = \dfrac{D}{d}

(c)

n = \dfrac{d}{D}

(d)

n = \dfrac{D+d}{D}