JEE Main 2022 · 30 Jul · Shift 2 · Physics Q24

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PhysicsInteger+4 / -1Question 24 of 90

A cell sends a current through a resistance 4 Ω for time t and sends current through another resistance 16 Ω for the same time t. If the same amount of heat is developed in both the resistances, then the internal resistance of the cell is _______ Ω

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Answer and worked solution

Official answer: 8

Equal heat. $\dfrac{E^2R_1}{(R_1+r)^2}=\dfrac{E^2R_2}{(R_2+r)^2}$ gives $r=\sqrt{R_1R_2}=\sqrt{64}=8$ Ω.

Answer: 8

Topics:EMF and internal resistance Electrical power and heating

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JEE Main 2022 · 30 Jul · Shift 2, Physics question 24