Practise O/L exam questions on Electricity and Magnetism with worked solutions
2023 · Paper II · 7 marks
Three resistors of 4 Ω, 6 Ω and 12 Ω are connected in parallel to a 12 V battery.
(i) Draw the circuit diagram.
(ii) Calculate the total resistance of the combination.
(iii) Calculate the total current drawn from the battery.
(iv) State Ohm's Law.
Show worked solution
(ii) 1/R_total = 1/4 + 1/6 + 1/12 = 3/12 + 2/12 + 1/12 = 6/12 → R_total = 2 Ω
(iii) I = V / R = 12 / 2 = 6 A
(iv) Ohm's Law: the current through a conductor is directly proportional to the potential difference across it, provided the temperature remains constant (V = IR).