Q1. Consider standing waves in an air column inside a pipe. One end of the pipe is open, and the other end is closed.
(a) Only even harmonics are present.
(b) Only odd harmonics are present.
(c) Both even and odd harmonics are present.
Q2. Consider a two-loop standing wave on a string. If we increase the tension without changing the frequency, what kind of standing wave can we obtain?
(a) one-loop
(b) three-loop
Q3. Beats are caused by the superposition of
(a) two waves with the same frequency, traveling in the same direction but out of phase with each other,
(b) two waves with the same frequency traveling in opposite directions, or
(c) two waves with slightly di?erent frequencies.