A tuning fork vibrating with a frequency of 512 Hz is kept close to the open end of a tube filled with water. The water level in the tube is gradually lowered. When the water level is 17 cm below the open end, the maximum intensity of sound is heard. If the room temperature is , calculate
a) speed of sound in air at room temperature
b) speed of sound in air at
c) if the water in the tube is replaced with mercury, will there be any difference in your observations?
(a) Pipe partially filled with water behaves like one end open organ pipe. The first harmonic is heard at L=17 cm
(b)
(c) Water and mercury in the tube reflect sound into the air column to form stationary waves and reflection is more in mercury compared to water because of its higher density. The intensity of sound heard in mercury will be larger, but the reading remains the same as the medium in the tube and the tunic fork does not change.