What is potential difference? Is it a scalar quantity or a vector quantity? Give its $SI$ units.

The equivalent resistance between points $A$ and $B$ in the following electric circuit is:

If the cross-sectional area of a conducting wire is doubled,what will be the effect on its resistance?

In the given circuit,calculate $(i)$ total resistance of the circuit,and (ii) current shown by the ammeter.

Find the number of electrons transferred between two points kept at a potential difference of $20 \ V$ if $40 \ J$ of work is done.

Read the following statements carefully and state whether each statement is true or false:
$(i)$ The quantity of charge flowing past a point multiplied by time is current.
$(ii)$ The flow of charge through a conducting wire connected to a cell is the result of a chemical reaction inside the cell.
$(iii)$ The resistivity of all pure metals increases with an increase in temperature.
$(iv)$ Ohm's law is a relation between the power used in a circuit to the current and the potential difference.
$(v)$ $A$ series circuit has only one conducting path for the electrons that move through it; a parallel circuit has multiple conducting paths.
$(vi)$ $A$ conducting wire offers resistance to the flow of electrons because electrons repel each other in the wire.