Kelper used total internal reflection in a glass block to deflect a beam of light as shown in the figure. For an angle of the incidence $i$ at the top surface, the minimum refractive index $(n)$ needed for total internal reflection at the vertical surface is (the surrounding medium is air for which $n = 1$ )

$n = 1 + s i n^{2} i$
$n = \sqrt{1 + s i n^{2} i}$
$n = \sqrt{1 + c o s^{2} i}$
$n = 1 + c o s^{2} i$

Question

Toppr Admin · Accepted Answer

Option B is correct