Q131 / 150 · MHT CET 2020 (13 Oct Shift 1) · Physics

In melde's experiment, when the tension decreases by $0.009$ kg-wt, the number of loops changes from 4 to $5 .$ The initial tension is

  • A
    $0.036$ kg-wt.
  • B
    $0 \cdot 009 \mathrm{~kg}$ -wt.
  • C
    $0 \cdot 018$ kg-wt.
  • Correct answer
    D
    $0.025$ kg-wt.

Solution

For Melde's experiment. $\mathrm{TP}^{2}=$ constant where $\mathrm{T}$ is the tension and $\mathrm{P}$ is the number of loops. $$ \begin{array}{l} \therefore \mathrm{T}_{1} \mathrm{P}_{1}{ }^{2}=\mathrm{T}_{2} \mathrm{P}_{2}{ }^{2} \\ \therefore \mathrm{T}_{1}(4)^{2}=\left(\mathrm{T}_{1}-0.009\right)(5)^{2} \\ \therefore 9 \mathrm{~T}_{1}=0.009 \times 25 \\ \therefore \mathrm{T}_{1}=0.025 \mathrm{~kg}-\mathrm{wt} \end{array} $$

Hence, the correct answer is option: 'D'.

Relevant Questions