Question

The refractive index of water is $(4 / 3)$ and that of glass is $(3 / 2)$.If the speed of light in glass is $2 \times 10^{8} \,m / s$. The speed of light in water will be :

• A. $1 \times 10^{8} \, m / s$
• B. $(9 / 4) \times 10^{8} \, m / s$
• C. $(8 / 3) \times 10^{8} \, m / s$
• D. $4 \times 10^{8} \,m / s$

Answer 1

Answer: (B)

$\frac{\mu_{1}}{\mu_{2}}=\frac{V_{1}}{V_{2}} $
$\Rightarrow \frac{\frac{3}{2}}{\frac{4}{3}}=\frac{C}{2 \times 10^{8}}$
$C=\frac{9}{4} \times 10^{8}$