JEE Main 2026 Apr 4 Shift 1, Physics Q18: Kirchhoff’s Laws

JEE Main2026Apr 4, Shift 1Physics

The voltage and the current between A and B points shown in the circuit are ________.

A
$24$ V, $12$ A
B
$24$ V, $4$ A
C
$18$ V, $12$ A
D
$27$ V, $4$ A

Solution

Use the equivalent EMF formula for parallel batteries (each branch contributing $\frac{E _{i}}{r _{i}}$ numerator and $\frac{1}{r _{i}}$ denominator). All four branches have effective EMF $27$ V and internal resistance $3 Ω$ :

$E_{eq} = \frac{27/3 + 27/3 + 27/3 + 27/3}{1/3 + 1/3 + 1/3 + 1/3} = \frac{36}{4/3} = 27 V .$

$r_{eq} = \frac{1}{4/3} = \frac{3}{4} Ω.$

The external resistor between $A$ and $B$ effectively is $6 Ω$ . Current:

$i = \frac{27}{6 + 3/4} = \frac{27}{27/4} = 4 A .$

$V_{A B} = i \cdot 6 = 24 V .$

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JEE Main 2026 Apr 4 Shift 1, Physics Q18: Kirchhoff’s Laws

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