🌊 Waves & Sound — Unit Quiz

A sound wave has frequency 680 Hz and travels through air at 340 m/s. What is its wavelength?

Which of the following is an example of a longitudinal wave?

The distance between two adjacent crests of a wave is called the:

A wave has frequency 5 Hz. What is its period?

A transverse wave travels to the right along a rope. Select ALL correct statements.

A string fixed at both ends has length 1.2 m and wave speed 48 m/s. What is the fundamental frequency?

A string of length 0.9 m vibrates in its third harmonic. How many complete wavelengths fit on the string?

A pipe open at both ends has length 0.68 m. What is the frequency of the second harmonic? (v_sound = 340 m/s)

Two waves with equal amplitudes of 3 cm meet at a point. They are exactly in phase (zero phase difference). What is the resulting amplitude at that point?

A standing wave is established on a string fixed at both ends. Select ALL correct statements.

A pipe closed at one end and open at the other has length 0.85 m. What is the frequency of the third harmonic? (v = 340 m/s)

A train horn emits 500 Hz. The train moves toward a stationary observer at 30 m/s. What frequency does the observer hear? (v_sound = 340 m/s)

Two speakers 2 m apart both play the same tone (λ = 0.8 m) in phase. A student stands equidistant from both speakers. Select ALL correct statements.

A guitar string (L = 0.65 m) produces a fundamental frequency of 260 Hz. (a) Find the wave speed on the string. (b) Find the frequencies of the 2nd and 3rd harmonics. (c) The tension is quadrupled. Given that wave speed is proportional to the square root of tension (v ∝ √T), find the new fundamental frequency.

A train moving at 30 m/s toward a stationary observer blows its horn at 500 Hz. The train then passes and moves away at the same speed. (v_sound = 340 m/s) (a) What frequency does the observer hear as the train approaches? (b) What frequency as it recedes? (c) What is the difference between the two frequencies? (d) Would the frequency difference increase or decrease if the train moved faster? Explain.