The fundamental frequency of a closed organ pipe of length 20 cm is equal to the second overtone of an organ pipe open at both the ends. The length of organ pipe open at both the ends is

If n₁, n₂ and n₃ are the fundamental frequencies of three segments into which a string is divided, then the original fundamental frequency n of the string is given by

A speeding motorcyclist sees traffic jam ahead him. He slows down to 36 km hour^$$-$$1. He finds that traffic has eased and a car moving ahead of him at 18 km hour^$$-$$1 is honking at a frequency of 1392 Hz. If the speed of sound is 343 m s^$$-$$1, the frequency of the honk as heard by him will be

The number of possible natural oscillations of air column in a pipe closed at one end length 85 cm whose frequencies lie below 1250 Hz are (Velocity of sound = 340 m s^$$-$$1)