In Searle's method to find Young's modulus of a wire, when a force of $1 \cdot 5 \mathrm{~kg}$ -wt is…
In Searle's method to find Young's modulus of a wire, when a force of $1 \cdot 5 \mathrm{~kg}$ -wt is applied at its free end, the length of wire is ' $a$ '. When force of $2 \cdot 5$ kg-wt is applied, the length of wire is 'b'. What would be its original length?
$\mathrm{b}-\mathrm{a}$
$\frac{\mathrm{b}-\mathrm{a}}{4}$
$2 \cdot 5 \mathrm{a}-1 \cdot 5 \mathrm{~b}$
$2 \cdot 5 \mathrm{~b}-1 \cdot 5 \mathrm{a}$
Solution
In Searle's method for determining the Young's modulus of a wire, the change in length $\Delta L$ caused by the applied force is related to the force itself. Using the provided lengths for two different applied forces, the original length of the wire can be calculated. Given that the force is applied at the free end, the original length $L_0$ is calculated based on the difference between the two lengths $a$ and $b$.
The correct answer is: 3
.