Question

Monochromatic light of frequency $5\times {10}^{14}$ Hz travelling in vacuum enters a medium of refractive index 1.5. Its wavelength in medium will be

• A. 5500 A
• B. 6000 A
• C. 4000 A
• D. 5000 A

Answer 1

The correct option is C 4000 A

Velocity of light $=3\times {10}^{8}m/s$

Wavelength $1=3\times {10}^{8}m/s÷5\times {10}^{1}4m/s=6000$ angstrom.

$N^2÷n^1=6000$ angstrom $÷$ wavelength

$2=1.5÷1=6000$ angstrom ÷ wavelength $2=4000$ angstrom.

Hence, Option $C$ is correct.