## College Physics (4th Edition)

When a wave moves from one medium to another medium, the frequency does not change. Since $v = \lambda~f$, and the frequency does not change, then the wavelength must change by the same percentage as the speed changes. We can find the percentage change of the wave speed: $\frac{1585~m/s-1450~m/s}{1450~m/s}\times 100\% = 9.3\%$ Therefore, the wavelength increases by 9.3%