The filament of a bulb takes a current 100 mA when potential difference across it is 0.2 V. When the potential difference across it becomes 1.0 V, the current becomes 400 mA. Calculate the resistance of filament in each case and account for the difference.

An electrical cell stores :

1. electrical energy
2. chemical energy
3. mechanical energy
4. potential energy

Emf of a cell is …………… the terminal voltage when cell is not in use, while …………… the terminal voltage when cell is in use.

1. greater than, smaller than
2. smaller than, greater than
3. equal to, greater than
4. equal to, smaller than

Current drawn from the cell :

1. I = ε[R+r]
2. I = $\dfrac{{\varepsilon}}{{(R + r)}}$
3. I = εR
4. I = $\dfrac{{E}}{{(r)}}$