Refractive index of glass is $1.5.$ Find the wavelength of a beam of light with a frequency of $10^{14} \mathrm{~Hz}$ in glass. Assume velocity of light is $3 \times 10^{8} \mathrm{~m} / \mathrm{s}$ in vacuum.
- $3 \; \mu \mathrm{m}$
- $3 \mathrm{~mm}$
- $2 \; \mu \mathrm{m}$
- $1 \; \mu \mathrm{m}$