A set of '\(n\)' equal resistors, of value '\(R\)' each, are connected in series to a battery of emf '\(E\)' and internal resistance '\(R\)'. The current drawn is \(I.\) Now, if '\(n\)' resistors are connected in parallel to the same battery, then the current drawn becomes \(10I.\) The value of '\(n\)' is:
1. \(10\)
2. \(11\)
3. \(20\)
4. \(9\)

The potential difference \(V_{A}-V_{B}\) between the points \({A}\) and \({B}\) in the given figure is:
     

Two metal wires of identical dimensions are connected in series. If \(\sigma_1~\text{and}~\sigma_2\) are the conductivities of the metal wires respectively, the effective conductivity of the combination is:
1. \(\dfrac{2\sigma_1 \sigma_2}{\sigma_1+\sigma_2}\)
2. \(\dfrac{\sigma_1 +\sigma_2}{2\sigma_1\sigma_2}\)
3. \(\dfrac{\sigma_1 +\sigma_2}{\sigma_1\sigma_2}\)
4. \(\dfrac{\sigma_1 \sigma_2}{\sigma_1+\sigma_2}\)

\({A, B}~\text{and}~{C}\) are voltmeters of resistance \(R,\) \(1.5R\) and \(3R\) respectively as shown in the figure above. When some potential difference is applied between \({X}\) and \({Y},\) the voltmeter readings are \({V}_{A},\) \({V}_{B}\) and \({V}_{C}\) respectively. Then:

        

Two cities are \(150~\text{km}\) apart. The electric power is sent from one city to another city through copper wires. The fall of potential per km is \(8~\text{volts}\) and the average resistance per \(\text{km}\) is \(0.5~\text{ohm}.\) The power loss in the wire is:

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: