Question

The speed of light in a given medium is 2/3 of its speed in vaccum the absolute refractive index of the ,edium equals to

Answer 1

We know that speed of light in vacum is
$3 \times {10}^{8} \frac{m}{sec}$
so the speed of light in medium by given condition will be
$\frac{2}{3} \times 3 \times {10}^{8}$
3 and 3 get cancelled out so speed of light in medium is
$2 \times {10}^{8}$
and so refractive undex of medium is
$\frac{3 \times {10}^{8} }{2 \times {10}^{8} }$
that is equal to
3/2=1.5

Therefore the R.I of medium is 1.5