Question

A ray of light is incident at the glass-water interface at an angle $i$. It merges finally parallel to the surface of the water. Then, the value of ${\mu }_g$ would be(where ${\mu }_g$ is the refractive index of glass with respect to water)

• A. $\left(4/3\right)\sin i$
• B. $1/\sin i$
• C. $4/3$
• D. $1$

Answer 1

The correct option is B $1/\sin i$

Using snell's law at water-glass surface, ${\mu }_{g}sini=\frac{4}{3}sinr$

Using snell's law at water-air surface, $1\times sin90=\frac{4}{3}sinr$

$⟹{\mu }_{g}sini=1$