Question

the siren of a stationary police car emits sound waves of wavelength 0.55m with its siren on the police car bow approaches a stationary listerner at constant velocity on a straight road assume that the speed of sound in the au=ir is 345m.s^-1.

1} will the wavelength of the sound wave observed by the listerner be GREATER THAN, SMALLER THAN or EQUALL TO 345m.s^-1

Answer 1

The wavelength observed by the listener will be smaller than 0.55m.

As the police car approaches the listener at a constant velocity, the wavelength of the sound waves will decrease due to the Doppler effect. This means that the sound waves will be "compressed" as the police car moves towards the listener, resulting in a smaller observed wavelength.

Therefore, the observed wavelength will be smaller than 0.55m.