Question

The speed of light in vacuum is c. The speed of light in a medium of refractive index \(\frac 43\) is

• A. \(\frac c3\)
• B. \(\frac c4\)
• C. \(\frac {4c}{3}\)
• D. \(\frac {3c}{4}\)

Answer 1

The Correct Option is D

The refractive index of a medium is defined as the ratio of the speed of light in vacuum (c) to the speed of light in the medium (v). 

$$ n = \frac{c}{v} $$ We are given the refractive index $n = \frac{4}{3}$. 

We want to find the speed of light in the medium, $v$. Rearranging the formula, we have $$ v = \frac{c}{n} = \frac{c}{\frac{4}{3}} = c \cdot \frac{3}{4} = \frac{3c}{4} $$ 

Therefore, the speed of light in the medium is $\frac{3c}{4}$.