A siren mounted on a moving vehicle produces sound that first travels through air and then enters the water of a nearby lake.
Answer the following questions about the same sound wave.
(a) Define (i) wavelength and (ii) frequency of a sound wave.
(b) Explain why the frequency of the sound remains unchanged when the wave passes from air into water even though its speed is different in the two media.
(c) Based on your explanation in part (b), state whether the wavelength of this sound in water will be larger, smaller, or equal to its wavelength in air. Give a reason for your answer.