A harmonic wave of wavelength 0.80m travels along a light string toward a junction with a heavier string. The wave speed in the light string is 4.0m/s, while in the heavier string it is 2.0m/s. Which of the following gives the ratio of the wavelength of the reflected wave in the light string to the wavelength of the transmitted wave in the heavier string?
a) 1:1
b) 2:1
c) 4:1
d) 1:2