Question

If the absolute refractive indices of glass and water are $\frac{3}{2}$ and $\frac{4}{3}$ respectively, what will be the velocity of light in water?

(If velocity of light in glass=$2\times {10}^8$)

• A. $2.25\times {10}^{8}m/s$
• B. $3.25\times {10}^{8}m/s$
• C. $2.25\times {10}^{7}m/s$
• D. $2.15\times {10}^{8}m/s$

Answer 1

The correct option is A $2.25\times {10}^{8}m/s$

Actually $n_g$=$\frac{3}{2}$ and $n_w$=$\frac{4}{3}$

The absolute refractive index of a medium=$\frac{speedoflight}{speedoflightinthemedium}$

Speed of light in glass=$2\times {10}^{8}m/s$

Speed of lighjt on vaccum $=dfrac32\times 2\times {10}^{8}m/s$

$=3\times {10}^8$

Speed of light in water$=\frac{3\times {10}^{8}m/s}{\frac{4}{3}}=2.25\times {10}^{8}m/s$