The refractive index of diamond is 2.0, velocity of light in diamond in metar per second is approximately:

The correct option is A $1.5\times {10}^{10}$

velocity of light in vacuum is $c=3\times {10}^{8}m/s$

refractive index of diamond is $\mu =2$

then,

velocity of light in diamond is $v=\frac{c}{\mu }=\frac{3\times {10}^{8}m/s}{2}=1.5\times {10}^{8}m/s$

velocity in cm/s is

$v=1.5\times {10}^{10}cm/s$

Option A is correct.