Question
Two heating elements of resistance R1 and R2 when operated at a constant supply of voltage, V, consume powers P1 and P2 respectively. Deduce the expressions for the power of their combination when they are, in turn, connected in (i) series and (ii) parallel across the same voltage supply.
Solution
i) When they are in series combination,
Net resistance, R = R1 + R2 … (1)
Heating elements are operated at same voltage V, we have
So, from equation (1), we have
ii) When the resistors are connected in parallel combination,
Net resistance is given by,
