The refractive indices of glass and water are 3/2 and 4/3, respectively. If the speed of light in water is $2.25 × 10^8\, m/s$, the speed of light in glass will be

$2× 10^8\, m/s$

The correct answer is Option (1) → $2× 10^8\, m/s$

Refractive index: $\mu = \frac{c}{v}$

Given: $\mu_\text{water} = 4/3$, $v_\text{water} = 2.25 \times 10^8\ \text{m/s}$, $\mu_\text{glass} = 3/2$

Speed of light in vacuum: $c = \mu_\text{water} \cdot v_\text{water} = \frac{4}{3} \cdot 2.25 \times 10^8 = 3 \times 10^8\ \text{m/s}$

Speed of light in glass: $v_\text{glass} = \frac{c}{\mu_\text{glass}} = \frac{3 \times 10^8}{3/2} = 2 \times 10^8\ \text{m/s}$

Final Answer: $v_\text{glass} = 2 \times 10^8\ \text{m/s}$