The potential difference in a circuit is 5V. There are two resistors connected in series of resistance 10 Ohms. Calculate the current I in the circuit.

Ohm's law states that V=IR ; where V is p.d., I is current and R is resistance.

Firstly the two resistors are in series so the total resistance is just the sum of the two resistances. Therefore R = 10+10 = 20 Ohms.

The potential difference V is 5V. 

By rearranging Ohm's law for the current I, I=V/R the current can be found by 5/20 = 0.25A