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Magnetic Effects & Magnetism

JEE Main level, single correct, medium

240 of 276

Question 240 of 276

Two long conductors, separated by a distance $\mathrm{d}$ carry current $\mathrm{I}_1$ and $\mathrm{I}_2$ in the same direction. They exert a force $F$ on each other. Now the current in one of them increased to two times and its direction reversed. The distance is also increased to $3 \mathrm{~d}$ . The new value of the force between them is

Show answer and solution

Answer: (C) $-2 F / 3$

Force between two long conductor carrying current

F=\frac{\mu_0}{2 \pi} \frac{l_1 l_2}{d} \ell

According to question

F^{\prime}=\frac{\mu_0}{2 \pi} \frac{\left(-2 I_1\right)\left(I_2\right)}{d} \ell

From equation (i) and (ii),

\mathrm{F}^{\prime}=-\frac{3}{2} \mathrm{~F}

JEE Main question paper PDF

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JEE Main 2025 Apr 2 Shift 1 question paper

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