In an open organ pipe $3 ^ { \text {rd } }$ and $6 ^ { \text {th } }$ harmonic frequency differ by 3200 Hz . Find the length of organ pipe (speed of sound $= 320 \mathrm {~m} / \mathrm { s }$ ) (A) 5 cm (B) 10 cm (c) 15 cm (D) 20 cm
In an open organ pipe $3 ^ { \text {rd } }$ and $6 ^ { \text {th } }$ harmonic frequency differ by 3200 Hz . Find the length of organ pipe (speed of sound $= 320 \mathrm {~m} / \mathrm { s }$ )
(A) 5 cm
(B) 10 cm
(c) 15 cm
(D) 20 cm