A tube that is open at both ends supports a standing wave with harmonics at 300 Hz and 400 Hz, with no harmonics between. What is the fundamental frequency of this tube?

A. 50 Hz

B. 100 Hz

C. 150 Hz

D. 200 Hz

E. 300 Hz

B. 100Hz

Explanation:

The resonant frequencies for a fixed string is given by the formula nv / (2L).

Where n is the multiple

v is speed in m/s

The difference between any two resonant frequencies is given by v / (2L) = fn+1 - fn

fundamental frequency means n=1

i. e fn+1 - fn = 400 - 300

= 100