A vertical tube

PHYSICS · Single correct · A Level · Physics · Waves · Waves

Problem

A vertical tube, closed at its lower end by water, is slowly drained. When a

512\,\text{Hz}

tuning fork is held over the tube, resonances are heard when the air column lengths are

18\,\text{cm}

and

54\,\text{cm}

. Based on these observations, which value is closest to the speed of sound in air? (a)

348\,\text{m}\,\text{s}^{-1}

(b)

360\,\text{m}\,\text{s}^{-1}

(c)

369\,\text{m}\,\text{s}^{-1}

(d)

390\,\text{m}\,\text{s}^{-1}