ExamBro
ExamBro
MHT CET · Physics · Current Electricity

In a potentiometer experiment, the balancing length for a cell \(240 \mathrm{~cm}\). On shunting the cell with a resistance of \(2 \Omega\), the balancing length become half the initial balancing length. The internal resistance of the cell is

  1. A \(1.5 \Omega\)
  2. B \(1 \Omega\)
  3. C \(0.5 \Omega\)
  4. D \(2 \Omega\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(2 \Omega\)

Step-by-step Solution

Detailed explanation

The internal resistance is given by
\(
\begin{aligned}
& r=R\left(\frac{\ell_1-\ell_2}{\ell_2}\right) \\
& =2\left(\frac{240-120}{120}\right)=2 \Omega
\end{aligned}
\)