An organ pipe has fundamental frequency 80 Hz . If its one end is closed, the frequencies produced will be (in Hz ) (Neglect end correction)

Step-by-step solution

An organ pipe of length L with fundamental frequency 80 Hz is initially open, satisfying v 2L = 80 , where v is the speed of sound. When one end is closed, it becomes a closed pipe with fundamental frequency f_ closed = v 4L = 1 2 80 = 40 Hz . Closed pipes produce only odd harmonics: f_ closed , 3f_ closed , 5f_ closed , 7f_ closed , Substituting 40 Hz yields the sequence 40, 120, 200, 280, Hz , which corresponds to option C .