AQA GCSE Parallel Circuit Calculations

1.Both bulbs are identical in the circuit below. Calculate the resistance of one of the bulbs in the circuit, when a current of 2.5 Amps flows through each bulb.

V= IR

R = V/I

R = 5/2.5 = 2 ohms

2. In the circuit below calculate the current that flows through the 21 ohm resistor

In the circuit above the potential difference across both resistors is the same as that of the cell, 12V.

V = IR

I = V/R

I = 12/21 = 0.57A

3. Calculate the potential differnce across the cell.

In a parallel circuit, the total current is the sum of the branches

2A+ 2A + 2A = 6A

V = I x R

V = 6A x 1.67 ohms

V = 10V

Practice Questions

1.Calculate the resistance of each bulb in the circuit below.

Calculation of current in a parallel circuit, using V = IR

2. The total resistance in the circuit below is 5 ohms. Calculate the potential difference of the cell in the circuit below.

3. In a parallel circuit, the potential difference across each component is 10V. The total current is 12A. The circuit contains only two bulbs and the cell. Calculate the resistance of each bulb.