Question

If speed of light in air is $3\times {10}^{8}m/s$ , the speed of light in glass (with refractive index 1.5) would be ________.

• A. $2\times {10}^{8}m/s$
• B. $4.5\times {10}^{8}m/s$
• C. $3\times {10}^{8}m/s$
• D. $1.5\times {10}^{8}m/s$

Answer 1

The correct option is A $2\times {10}^{8}m/s$

Refractive ($\mu$) = $\frac{speedoflightinvacuum}{speedoflightinmedium}$

speed of light in medium(glass) = $\frac{3\times {10}^8}{1.5}$ = $2\times {10}^8$ m/s