State the sign convention for applying Kirchhoff's first rule.

Explanation

Rule follows from the law of coservation of energy for an isolated system (The energy supplied by the emf sources is equal to the sum of the energy delivered to all resistors). The product of current and resistance is taken as positive when the direction of the current is followed. Suppose if the direction of current is opposite to the direction of the loop, then product of current and voltage across the resistor is negative. The efm is considered positive when proceeding from the negative to the positive terminal of the cell.