波的一般性質：练习题

A longitudinal sound wave travels through air at a speed of \( 330\text{ m/s} \). If the frequency of the source is \( 165\text{ Hz} \), what is the distance between a compression and the adjacent rarefaction?

A radio station transmits signals with a wavelength of \( 1500\text{ m} \). These signals can be received in a valley behind a large hill, whereas TV signals with a wavelength of \( 0.5\text{ m} \) cannot. Which wave property explains this difference?

Explain, in terms of oscillations, why a sound wave is described as a longitudinal wave.

A local radio station broadcasts at a frequency of \( 102\text{ MHz} \). Given that all electromagnetic waves travel at \( 3.0 \times 10^{8}\text{ m/s} \) in a vacuum, calculate the wavelength of these radio waves. Give your answer to two significant figures.

A series of water waves with a wavelength of \( 0.08\text{ m} \) approach a gap in a barrier. Describe and explain how the pattern of the waves changes after passing through the gap if the width of the gap is reduced from \( 0.50\text{ m} \) to \( 0.08\text{ m} \).

A water wave travels from deep water into a shallower region.
(a) The wave has a frequency of \(4.0\text{ Hz}\) and a wavelength of \(0.15\text{ m}\) in deep water. Calculate the wave speed.
(b) In the shallower water, the speed of the wave decreases to \(0.40\text{ m/s}\). Calculate the new wavelength, assuming the frequency remains unchanged.
(c) Explain why the direction of a wave changes when it enters a new medium at an angle, referring to the change in speed.