Answer
The four lowest standing wave frequencies are:
$f_1 = 17.9~Hz$
$f_3 = 53.7~Hz$
$f_5 = 89.5~Hz$
$f_7 = 125.3~Hz$
Work Step by Step
We can find the fundamental frequency:
$f = \frac{v}{\lambda}$
$f = \frac{v}{4L}$
$f = \frac{343~m/s}{(4)(4.80~m)}$
$f = 17.9~Hz$
In a pipe that is closed at one end, the standing wave frequencies have the form $~f, ~3f, ~5f, ~7f, ~9f, ~etc...$
We can find the four lowest standing wave frequencies:
$f_1 = 17.9~Hz$
$f_3 = (3)(17.9~Hz) = 53.7~Hz$
$f_5 = (5)(17.9~Hz) = 89.5~Hz$
$f_7 = (7)(17.9~Hz) = 125.3~Hz$
