# For an equilateral prism, it is observed that when a ray strikes grazingly at one face it emerges grazingly at the other. Its refractive index will be

Q: For an equilateral prism, it is observed that when a ray strikes grazingly at one face it emerges grazingly at the other. Its refractive index will be

Sol: i1 = i2 = 90° ,r1 = r2 = A/2 = 30°

$\large \mu = \frac{sini_1}{sinr_1}$

$\large \mu = \frac{sin90^o}{sin30^o}$

μ = 2