A factory siren emits a continuous sound wave whose wavelength in air at 20∘C is 50cm.
(a) Taking the speed of sound in air as 343m/s, calculate the frequency of the siren.
(b) The same siren is attached to a research submarine. Under water, the speed of sound is 1530m/s. Keeping the frequency unchanged, calculate the wavelength of the sound in seawater. Express your answer in metres and in centimetres.
(c) The submarine emits this sound pulse and receives its reflection from the seabed after 0.80s. Calculate the depth of the sea at that location.