JEE Main 2026 Jan 21 Shift 2, Physics Q10: Energy, Power And Heating Effect

JEE Main2026Jan 21, Shift 2Physics

A battery with EMF E and internal resistance r is connected across a resistance R. The power consumption in R will be maximum when :

Solution

Maximum power transfer to a load happens when the load resistance equals the source's internal resistance. So $R = r$ .

(Quick check: $P_{R} = \frac{E ^{2} R}{( R + r ) ^{2}}$ ; setting $\frac{d P _{R}}{d R} = 0$ gives $R = r$ .)

Concept behind this question

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