A tuning fork vibrates at a frequency of 256Hz. The sound produced by it travels through air at 340ms−1 and through helium at 970ms−1.
(a) Calculate the wavelength of the sound in air.
(b) Determine the wavelength of the same sound in helium.
(c) Which quantity, frequency or wavelength, changes when the sound moves from air to helium? Justify your answer briefly based on your calculations.