The resistivity of a material does not change if:

Why is very less heat generated in long electric cables than in filaments of electric bulbs?

Calculate the number of electrons that would flow per second through the cross-section of a wire when $1 \, A$ current flows in it.

Give a single word for $\frac{1 \text{ joule}}{1 \text{ coulomb}}$.

List any two factors on which the resistance of a conductor depends.

When a high resistance voltmeter is connected directly across an electric bulb,its reading is $2 \ V$. An electric cell is sending a current of $0.4 \ A$ (measured by an ammeter) in the electric circuit.
$(a)$ Draw the circuit.
$(b)$ Find the resistance of the electric bulb.
$(c)$ State the law that is applied for making these calculations. If a graph is plotted between $V$ and $I$,show the nature of the graph obtained.