Question

The displacement-time graph of a sound wave produced by a vibrating wire is shown below.

1. How will you adjust the tension in the wire, to reduce the length of PR?
2. Which characteristic of sound is affected by the reduction in the length of PR?

Answer 1

a. We know that frequency is directly proportional to square root of tension in the string    ...[law of vibrating string]

f = `1/T`

= `1/(2l) sqrt(T/m)`

So, to reduce the length of PR (time period), we need to increase tension. |

b. By reducing the duration of the PR (time period), the frequency increases, hence elevating the pitch of sound.