A glass has refractive index 3/2 and water has refractive index 4/3. If the speed of light in glass is 2 × 108 m/s the speed of light in water in m/s is

Question

A glass has refractive index 3/2 and water has refractive index 4/3. If the speed of light in glass is 2 × 108 m/s the speed of light in water in m/s is (A) 1.5 × 106 (B) 1.78 × 108 (C) 2.25 × 108 (D) 2.67 × 108

Tardigrade Admin · Accepted Answer

Since, μ v= constant ⇒ μg vg =μw vw ⇒ (3/2)(2 × 108) =(4/3) vw ⇒ vw =2.25 × 108 m / s

Q. A glass has refractive index $3/2$ and water has refractive index $4/3$ . If the speed of light in glass is $2 \times 1 0^{8} m / s$ the speed of light in water in $m / s$ is

$1.5 \times 1 0^{6}$

$1.78 \times 1 0^{8}$

$2.25 \times 1 0^{8}$

$2.67 \times 1 0^{8}$

Since, $μv =$ constant
$\Rightarrow μ_{g} v_{g} = μ_{w} v_{w}$
$\Rightarrow \frac{3}{2} (2 \times 1 0^{8}) = \frac{4}{3} v_{w}$
$\Rightarrow v_{w} = 2.25 \times 1 0^{8} m / s$

Q. A glass has refractive index 3/2 and water has refractive index 4/3. If the speed of light in glass is 2×108m/s the speed of light in water in m/s is

1.5×106

1.78×108

2.25×108

2.67×108