Question

The speed of light in a piece of crown glass is $2\times {10}^{5}m/s$. Find out the refractive index of crown glass?

• A. 2
• B. 1500
• C. 0.67
• D. 0.33
• E. 0.2

Answer 1

The correct option is B 1500

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

Speed of light in crown glass $v=2\times {10}^5$ m/s

Thus refractive index of crown glass $n_{glass}=\frac{c}{v}=\frac{3\times {10}^8}{2\times {10}^5}=1500$