A circuit contains three resistors 12Ω, 18Ω and 24Ω each connected in its own branch in parallel across a constant 30V supply. The branch with the 24Ω resistor has a switch S in series, so that this resistor can be connected or disconnected without disturbing the other two branches.
Using this information, answer the questions below.
(i) With switch S open, calculate the power dissipated in the 12Ω resistor, the 18Ω resistor and the total power in the circuit.
(ii) When switch S is closed, calculate the new power dissipated in each of the three resistors and the new total power. What is the percentage increase in total power when S is closed?
(iii) For the case when S is closed, determine which resistor produces the maximum heat in 60s and justify your answer with numerical values.