Moving Charges and Magnetism - Result Question 65

66. A square loop, carrying a steady current I, is placed in a horizontal plane near a long straight conductor carrying a steady current $I_1$ at a distance $d$ from the conductor as shown in figure. The loop will experience

[2011M]

(a) a net repulsive force away from the conductor

(b) a net torque acting upward perpendicular to the horizontal plane

(c) a net torque acting downward normal to the horizontal plane

(d) a net attractive force towards the conductor

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Answer:

Correct Answer: 66. (d)

Solution:

(d)

$F_1>F_2$ as $F \propto \frac{1}{d}$, and $F_3$ and $F_4$ are equal and opposite. Hence, the net attraction force will be towards the conductor.