The figure given below shows a circuit when resistances in the two arms of the meter bridge are \(5~\Omega\) and \(R\), respectively. When the resistance \(R\) is shunted with equal resistance, the new balance point is at \(1.6l_1\). The resistance \(R\) is:
1. | \(10~\Omega\) | 2. | \(15~\Omega\) |
3. | \(20~\Omega\) | 4. | \(25~\Omega\) |