Question

The time required for light to pass through a glass slab of $2mm$ thickness is (${\mu }_{glass}=1.5$)

• A. ${10}^{-8} s$
• B. ${10}^{-6} s$
• C. ${10}^{-11} s$
• D. none of these

Answer 1

The correct option is C

${10}^{-11} s$

Step 1: Given

1. Refractive index of glass ${\mu }_g=1.5$.
2. Thickness $d=2 mm=2\times {10}^{-3}m$.

Step 2: Calculating time required

1. We know that $\text{time(}t)=\frac{d}{v}\text{and}v=\frac{c}{\mu }$
2. So, $t=\frac{d\mu }{c}=\frac{2\times {10}^{-3}\times 1.5}{3\times {10}^8}={10}^{-11}s$.

Hence, the correct option is (c) ${10}^{-11} s$.