$1 \; kWh = \ldots \ldots \ldots \; \text{watt-seconds}$

In an experimental set-up as shown below,a piece of silver was placed touching points $A$ and $B$. Next time it was replaced by a piece of wood. In which case did the bulb glow? Give reason to justify the observation.

Find the equivalent resistance of the following circuit.

$A$ current of $0.5\, A$ is drawn by a filament of an electric bulb for $10$ minutes. Find the amount of electric charge that flows through the circuit. (in $C$)

Why is heat produced when a current is passed through a conductor?

Define resistivity of a material.