A source of sound gives 5 beats per second, when sounded with another source of frequency 100 second⁻¹. The second harmonic of the source, together with a source of frequency 205 sec⁻¹ gives 5 beats per second. What is the frequency of the source?

Question

Accepted Answer

(1) 105 second⁻¹. Given: |f-100|=5, and |2f-205|=5. Idea: the first condition gives two candidates, and the second picks between them. f=105 or f=95. If f=105: 2f=210, and |210-205|=5. That fits. If f=95: 2f=190, and |190-205|=15. That does not. f=105 second⁻¹.

A source of sound gives 5 beats per second, when sounded with another source of frequency 100 second⁻¹. The second harmonic of the source, together with a source of frequency 205 sec⁻¹ gives 5 beats per second. What is the frequency of the source?

Step-by-step solution

Why the other options are wrong