Join the Most Relevant JEE Main 2025 Test Series & get 99+ percentile! Join Now
Search any question & find its solution
Question: Answered & Verified by Expert
A square loop $A B C D$, carrying a current $I_2$, is placed near and coplanar with a long straight conductor $X Y$ carrying a current $I_1$, as shown in figure. The net force on the loop will be

PhysicsMagnetic Effects of CurrentAIIMSAIIMS 2017
Options:
  • A $\frac{\mu_0 I_1 I_2}{2 \pi}$
  • B $\frac{\mu_0 I_1 I_2 L}{2 \pi}$
  • C $\frac{2 \mu_0 I_1 I_2 L}{3 \pi}$
  • D $\frac{2 \mu_0 I_1 I_2}{3 \pi}$
Solution:
2973 Upvotes Verified Answer
The correct answer is: $\frac{2 \mu_0 I_1 I_2}{3 \pi}$
Force on arm $A B$ due to current in conductor $X Y$ is
$F_1=\frac{\mu_0}{4 \pi} \frac{2 I_1 I_2 L}{(L / 2)}=\frac{\mu_0 I_1 I_2}{\pi}$ acting towards the wire in the plane of loop.
Force on arm $C D$ due to current in conductor $X Y$ is
$F_2=\frac{\mu_0}{4 \pi} \frac{2 I_1 I_2 L}{(3 L / 2)}=\frac{\mu_0 I_1 I_2}{3 \pi}$ away from the wire the plane of loop.
$\therefore \quad$ Net force on the loop $=F_1-F_2$
$=\frac{\mu_0 I_1 I_2}{\pi}\left[1-\frac{1}{3}\right]=\frac{2}{3} \frac{\mu_0 I_1 I_2}{\pi}$

Looking for more such questions to practice?

Download the MARKS App - The ultimate prep app for IIT JEE & NEET with chapter-wise PYQs, revision notes, formula sheets, custom tests & much more.