Wave Motion 4 Question 32
30. A string long and having a mass of is under tension. A pipe closed at one end is long. When the string is set vibrating in its first overtone and the air in the pipe in its fundamental frequency, 8 beats/s are heard. It is observed that decreasing the tension in the string decreases the beat frequency. If the speed of sound in air is find the tension in the string.
(1982, 7M)
Show Answer
Answer:
Correct Answer: 30. (a, b, c, d)
Solution:
- By decreasing the tension in the string beat frequency is decreasing, it means frequency of string was greater than frequency of pipe. Thus,
First overtone frequency of string - Fundamental frequency of closed pipe
Substituting the value, we have