## Physics for Scientists and Engineers: A Strategic Approach with Modern Physics (3rd Edition)

We can find the speed in the liquid as: $v = \frac{d}{t}$ $v = \frac{0.30~m}{1.38\times 10^{-9}~s}$ $v = 2.174\times 10^8~m/s$ We can find the index of refraction of the liquid as: $v = \frac{c}{n}$ $n = \frac{c}{v}$ $n = \frac{3.0\times 10^8~m/s}{2.174\times 10^8~m/s}$ $n = 1.38$ We can find the wavelength in the liquid as: $n = \frac{\lambda_a}{\lambda_l}$ $\lambda_l = \frac{\lambda_a}{n}$ $\lambda_l = \frac{633~nm}{1.38}$ $\lambda_l = 459~nm$ The wavelength of the laser beam in the liquid is 459 nm.