current electricity Questions

The effective resistance of a parallel connection that consists of four wires of equal length, equal area of cross-section and same material is $0.25\Omega$. What will be the effective resistance if they are connected in series?

Column-I gives certain physical terms associated with flow of current through a metallic conductor. Column-II gives some mathematical relations involving electrical quantities. Match Column-I and Column-II with appropriate relations.

In a potentiometer circuit a cell of EMF $1.5\text{V}$ gives balance point at $36\text{cm}$ length of wire. If another cell of EMF $2.5\text{V}$ replaces the first cell, then at what length of the wire, the balance point occurs?

Three resistors having resistance $r_1,r_2$, and $r_3$ are connected as shown in the given circuit. The ratio $i_3/i_1$ of currents in terms of resistances used in the circuit is: