The potentiometer is best for measuring voltage, as:

1. It has a sensitive galvanometer
2. It has wire of high resistance
3. It measures p.d. like in closed circuit
4. It measures p.d. like in open circuit

When three identical bulbs of \(60~\text{watts}\) and \(200~\text{volt}\) rating are connected in series to a \(200~\text{volt}\) supply, the power drawn by them will be:
1. \(180~\text{watt}\)
2. \(10~\text{watt}\)
3. \(20~\text{watt}\)
4. \(60~\text{watt}\)

The electric resistance of a particular wire of iron is \(R.\) If its length and radius are doubled, then:

Resistances \(n,\) each of \(r~\text{ohm},\)  when connected in parallel give an equivalent resistance of \(R~\text{ohm}.\) If these resistances were connected in series, the combination would have resistance in \(\text{ohms}\) equal to:
1. \(\dfrac{R}{n^2}\)
2. \(\dfrac{R}{n}\)
3. \(nR\)
4. \(n^2R\)

The current in \(8~\Omega\) resistance is (in the figure below):

1. \(0.69\) A
2. \(0.92\) A
3. \(1.30\) A
4. \(1.6\) A

If the power dissipated in \(5~\Omega\) is \(20~\text{W}\) then the power dissipated in \(4~\Omega\) is:
   
1. \(4~\text{W}\)
2. \(6~\text{W}\)
3. ​​​​​​​\(10~\text{W}\) 
4. ​​​​​​​\(20~\text{W}\)

The terminal potential difference of a cell is greater than its emf when:

In India, electricity is supplied for domestic use at \(220~\text{V}.\) It is supplied at \(110~\text{V}\) in the USA. If the resistance of a \(60~\text{W}\) bulb for use in India is \(R\), the resistance of a \(60~\text{W}\) bulb for use in the USA will be:

A battery is charged at a potential of \(15\) V for \(8\) hours when the current flowing is \(10\) A. The battery on discharge supplies a current of \(5\) A for \(15\) hours. The mean terminal voltage during discharges is \(14\) V. The "Watt hour" efficiency of the battery is:
1. \(80\%\)
2. \(90\%\)
3. \(87.5\%\)
4. \(82.5\%\)