An electron in a metal is free to move anywhere but cannot leave the metal.

What will be the equivalent resistance between points $A$ and $B$ of the following electric circuit?

The filament of an electric bulb is made of tungsten. Why?

If $2 \times 10^{-3} \text{ J}$ of work is done in moving a particle carrying a charge of $10 \times 10^{-6} \text{ C}$ from infinity to a point $P$, what will be the potential at the point $P$ (in $\text{ V}$)?

The electric current flowing through any conductor is directly proportional to the electric potential difference across the conductor. Which law is this?

If the diameter of a conducting wire is doubled,how many times does its resistance become?