Question

5.A longitudinal wave is generated by buzzer that vibrates with a frequency of 600Hz . it travels through a metal bar with a wavelength of 9m . when the wave meets air ,it is able to travel through the air with a wavelength of 0,55m .


5.1calculate the speed of the wave in the metal bar .

5.2 calculate the speed of the wave in the air .

5.3 explain why the frequency remains constant.

Answer 1

5.1. $c_{metal} = f\lambda_{metal} = 600~\text{Hz}~*~9~\text{m} = 5400\frac{\text{m}}{\text{s}}. \\$

5.2. $c_{air} = f\lambda_{air} = 600~\text{Hz}~*~0.55~\text{m} = 330\frac{\text{m}}{\text{s}}. \\$

5.3. The frequency depends upon the source of the vibration (i.e. the buzzer), not the medium of propagation.