Question

A closed organ pipe and an open organ pipe of the same length produce four beats, when sounded together. If the length of the closed organ pipe is increased, then the number of beats will 

(a) remains the same 

(b) increase 

(c) decrease 

(d) first (b) then (a).

Answer 1

Correct option  (b) increase 

Explanation:

The fundamental frequency of the open organ pipe is given by v_open = v/2L

The beat frequency is v_open - v_close = 4

Now. if we increase the length of the closed pipe then the frequency v_close is going to decrease.

 The beat frequency v_open - v_close  is going to increase.