Beats with SonometerHardQuestion 31340
Question
String vibrates at f₁. Another string of same material and length under different tension vibrates at f₂. If f₂ > f₁ and 6 beats/second are heard, and increasing tension of string 1 by 1% increases beats to 7, then:
- Af₂ is higher by 6 Hz initially
- Bf₁ increased by less than 6 Hz with 1% tension increase
- Cf₁ was 600 Hz originally
- DBoth A and BCorrect
Correct answer
Both A and B
Explanation
f₂−f₁ = 6. Adding 1% tension: f₁ → f₁√1.01 ≈ f₁(1+0.005). Δf₁ = 0.005f₁. Beats become 7: f₂−f₁(new) = 7 → f₁ increased by 1 Hz → 0.005f₁ = 1 → f₁ = 200 Hz. So f₂ is 6 Hz higher and tension increase adds less than 6 Hz.