The frequency driving an open-closed tube is steadily raised. Resonances are heard at 500 Hz and 700 Hz with none in between. What is the fundamental and next highest harmonic frequency? Select the correct answer O 100 Hz, 300 Hz O 200 Hz, 300 Hz O 100 Hz, 200Hz O 200 Hz, 400 Hz

100, 300 Hz.

Explanation:

In closed organ pipe only odd harmonics are sounded. The frequency sounded are 500 and 700. If we take fundamental as 200, odd harmonics will have frequency of 600 (3 times), 1000 (5 times). So 100 is not the fundamental frequency.

If we take 100 as fundamental, higher harmonics will be 300 (3 times)

5 times (500) or 700 (7 times)

So 100 is the fundamental frequency

The required frequencies are 100, 300 Hz.