A pressure wave is a longitudinal wave made of alternating regions of higher and lower pressure moving through a medium.
Instead of crests and troughs, the medium gets squeezed and spread out as the wave passes.
Showing a random 20 of 50 problems.
Example 1
hard
Sound intensity is given by I=ΔP2/(2ρv) where ρ is air density and v is sound speed. For ΔP=0.6 Pa, ρ=1.2 kg/m3, v=340 m/s, find the intensity.
Example 2
medium
A pressure wave is plotted with pressure on the y-axis and position on the x-axis. What single quantity does the x-distance between adjacent peaks represent?
Example 3
easy
Sound at 20∘C in air travels at about 343 m/s. Does increasing temperature increase or decrease the speed?
Example 4
easy
The distance between a compression and the next rarefaction is 0.25 m. Find the wavelength.
Example 5
easy
In a pressure wave, what are the high-pressure regions called?
Example 6
medium
A microphone records 1200 compressions arriving in 2.0 s. Find the wave's frequency.
Example 7
medium
Two compressions and the rarefaction between them span 0.9 m. What is the wavelength?
Example 8
medium
A sound wave's wavelength is 1.36 m in air (340 m/s). Find its period.
Example 9
easy
Pressure waves alternate between regions of high and low pressure. What two names label these regions?
Example 10
hard
Two coherent loudspeakers 1.7 m apart emit pure 200 Hz tones in phase (v=340 m/s). A listener stands on the perpendicular bisector. Will the speakers' sounds reinforce, cancel, or partially overlap there?
Example 11
medium
Using the same wave ΔP=(2 Pa)sin(2π(680t−2x)), find the wave's speed.
Example 12
medium
A pressure sensor reads atmospheric pressure plus a fluctuation peaking at +2 Pa and dipping to -2 Pa. What is the pressure amplitude of the wave?
Example 13
challenge
A pulse with pressure amplitude 0.4 Pa in air (ρ=1.2 kg/m3, v=340 m/s) spreads as a spherical wave from a point source. Use I=ΔP2/(2ρv) at the 1.0 m radius. What is the source's total power (assume isotropic emission)?
Example 14
hard
Two coherent in-phase speakers separated by 0.85 m emit 400 Hz tones (v=340 m/s). A listener directly in front of one speaker (so the path difference equals the speaker separation) experiences what type of interference?
Example 15
easy
A sound wave's wavelength in air is 0.10 m and v=340 m/s. Find its frequency.
Example 16
easy
A pressure wave's amplitude is 0.5 Pa above atmospheric. What is its peak-to-peak pressure variation?
Example 17
medium
If a sound wave's pressure amplitude doubles, what happens to its frequency?
Example 18
medium
A loudspeaker emits sound at 250 Hz. A pressure probe sits exactly λ/4 from the speaker. What is the phase difference between the speaker's vibration and the pressure at the probe?
Example 19
easy
Can a pressure (sound) wave travel through a vacuum?
Example 20
easy
A sound has period T=0.005 s and travels in air at 340 m/s. Find its wavelength.