Wave Motion> A tuning fork vibrating with sonometre wi...

A tuning fork vibrating with sonometre wire of length 20cm produces 5 beats per second . The beat frequency doesn't change if length of wire is changed to 21cm , the frequency of tuning fork is

Pavan , 7 Years ago

Grade 12

2 Answers

Arun

Last Activity: 7 Years ago

Fundamental frequency is:
n = 1/2l √T/m
n 1/l
assume for 20cm frequency is n₁
and for 21 cm frequency is n₂
So
n₁/n₂ = 21/20
then n₁ = 21x and n₂ = 20x
Let frequency nf for producing 5 beats so n₁ > n_f > n₂
So n₁ - n_f = 5
21x - n_f = 5 ....(i)
And n_f - n₂ = 5
n_f - 20x = 5 .....(ii)
from (1) ans (2) we get x = 205 hz

Rishi Sharma

Last Activity: 4 Years ago

Dear Student,
Please find below the solution to your problem.

Fundamental frequency is:
n = 1/2l√T/m
n 1/l
assume for 20cm frequency is n1
and for 21 cm frequency is n2
So
n1/n2= 21/20
then n1= 21x and n2= 20x
Let frequency nf for producing 5 beats so n1> nf> n2
So n1- nf= 5
21x - nf= 5 ....(i)
And nf- n2= 5
nf- 20x = 5 .....(ii)
from (1) ans (2) we get x = 205 hz

Thanks and Regards