MCQ
Two identical wires have the same fundamental frequency of $400\ \mathrm{Hz}$. when kept under the same tension. If the tension in one wire is increased by $2 \%$ the number of beats produced will be
- ✓$4$
- B$2$
- C$8$
- D$1$
✓
Answer
Correct option: A.
$4$
$n \propto \sqrt{T} \Rightarrow \frac{\Delta n}{n}=\frac{1}{2} \frac{\Delta T}{T}$
$\text { Beat frequency }=\Delta n=\left(\frac{1}{2} \frac{\Delta T}{T}\right) n=\frac{1}{2} \times \frac{2}{100} \times 400=4$
$\text { Beat frequency }=\Delta n=\left(\frac{1}{2} \frac{\Delta T}{T}\right) n=\frac{1}{2} \times \frac{2}{100} \times 400=4$
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