A wave disturbance travelling in air enters a medium in which its velocity is less than that in air. Which of the following statements is true about the wave medium?
-
A.
both the frequency of the wave and the wavelength are decreased -
B.
the frequency of the wave is decreased while the wavelength is increased -
C.
the frequency of the wave is unaltered while the wavelength is decreased -
D.
the frequency of the wave is decreased while the wavelength is unaltered