AP EAMCET2010PhysicsWaves and Sound
A sonometer wire has a length of 114 ~cm , between two fixed ends. Where should two bridges be placed so as to divide the wire into three segments (in cm ) whose fundamental frequencies are in the ratio 1: 3: 4 ?
Options
- Al₁, l₂, l₃=18,24,72
- Bl₁, l₂, l₃=24,18,72
- Cl₁, l₂, l₃=72,18,24
- Dl₁, l₂, l₃=72,24,18
Correct answer
D. l₁, l₂, l₃=72,24,18
Step-by-step solution
If length of the wire between the two bridges is l , the frequency of vibration n= 1 2 l T m n 1 l Therefore, n₁: n₂: n₃= 1 l₁ : 1 l₂ : 1 l₃ n₁: n₂: n₃= 1 114 1 8 : 1 114 3 8 : 1 114 4 8 or n₁: n₂: n₃=8: 8 3 : 2 or n₁: n₂: n₃=72: 24: 18