Two identical heater filaments are connected first in parallel and then in series. At the same applied voltage, the ratio of heat produced in the same time, parallel : series, is:
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Question

Two identical heater filaments are connected first in parallel and then in series. At the same applied voltage, the ratio of heat produced in the same time, parallel : series, is:

G1 Physics · Accepted Answer

For two equal resistances R: R(parallel)=R/2 and R(series)=2R. At fixed V and t, H = V²t/R(eq). H(parallel)/H(series) = (2R)/(R/2) = 4. Ratio = 4:1.