Question

What is the speed of light in glass if the index of refraction of the glass is $1.63$?

• A. $4.89\times {10}^{8}m/s$
• B. $5.43\times {10}^{-9}m/s$
• C. $3.00\times {10}^{8}m/s$
• D. $1.84\times {10}^{8}m/s$
• E. $4.63\times {10}^{8}m/s$

Answer 1

Answer: (D)

$1.84\times {10}^{8}m/s$

Speed of light in air $c=3\times {10}^8$ m/s

Refractive index of glass $n=1.63$

$\therefore$ Speed of light in glass $v=\frac{c}{n}=\frac{3\times {10}^8}{1.63}=1.84\times {10}^8$ m/s