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JEE Main 2023 (25 Jan, Shift 2) · Cells: EMF, Internal Resistance & Combinations

Cells: EMF, Internal Resistance & Combinations question from JEE Main 2023 (25 Jan, Shift 2)

Q18JEE Main 2023 · 25 JAN · SHIFT 2Medium

Cells: EMF, Internal Resistance & Combinations

Two cells are connected between points A and B as shown. Cell 1 has emf of 12 V and internal resistance of 3Ω\Omega. Cell 2 has emf of 6V and internal resistance of 6Ω\Omega. An external resistor R of 4Ω\Omega is connected across A and B. The current flowing through R will be ____________ A.

Figure

Numerical answer type. Work it out, then open the answer.

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Answer: 1

  1. From the figure the two cells are in parallel with opposite polarity.
  2. Eeq=E1/r1−E2/r21/r1+1/r2=12/3−6/61/3+1/6=31/2=6 VE_{eq} = \dfrac{E_1/r_1 - E_2/r_2}{1/r_1 + 1/r_2} = \dfrac{12/3 - 6/6}{1/3 + 1/6} = \dfrac{3}{1/2} = 6\text{ V}
  3. req=3×63+6=2 Ωr_{eq} = \dfrac{3 \times 6}{3 + 6} = 2\ \Omega
  4. I=62+4=1 AI = \dfrac{6}{2 + 4} = 1\text{ A}
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