# When light of wavelength λ0 in vacuum travels through same thickness ‘ t  ’ in glass and water, the difference in the number of waves is ….

Q: When light of wavelength λ0 in vacuum travels through same thickness ‘ t  ’ in glass and water, the difference in the number of waves is …. (Refractive indices of glass and water are μg and w respectively.)

Sol: We know number of waves of a given light in a medium of refractive index μ is (t μ)/λ0

Difference in number of waves $\large = \frac{t}{\lambda_0} (\mu_0 – \mu_w)$

Where μg and μw are the refractive indices of glass and water respectively.