NTA Abhyas JEE Main2020PhysicsWaves and SoundPractice
Two identical piano wires have a fundamental frequency of 600 cycle per second when kept under the same tension. What fractional increase in the tension of wires will lead to the occurrence of 6 beats per second when both wires vibrate simultaneously?
Options
- A0 . 01
- B0 . 02
- C0 . 03
- D0 . 04
Correct answer
B. 0 . 02
Step-by-step solution
Beats per second when both the wires vibrate simultaneously n 1 ± n 2 = 6 or 1 2 l ⁡ T m ± 1 2 l ⁡ T ' m = 6 or 1 2 l ⁡ T ' m - 1 2 l ⁡ T m = 6 or 1 2 l ⁡ T ' m - 6 0 0 = 6 ...(i) Given that fundamental frequency 1 2 l T m = 600 Dividing Eq.(i) by Eq. (ii), we get 1 2 l ⁡ T ' m 1 2 l ⁡ T m = 6 0 6 6 0 0 Or T ' T = 1.01 Or T ⁡ ′ T ⁡ = 1 . 0 2 % Or T '   = T   ( 1 . 02 ) Increase in tension Δ T '   =   ( T   × &