Question

Two identical conductors 1 and 2 are placed on two frictionless conducting rails R and S in a uniform magnetic field directed vertically downward into the plane of the page. If conductor 1 is moved with a constant velocity in the direction as shown in figure, the force on conductor 2 will be along :

• A. \( -\hat{i} \)
• B. \( - \hat{j} \)
• C. \( \hat{k} \)
• D. \( \hat{j} \)

Hint:

Save time by analyzing this via energy conservation and Lenz's Law directly: Lenz's Law states that any induced effect always attempts to destroy the cause that created it. Here, the cause of the induction is the expansion of the loop's area due to conductor 1 moving left. To counteract this growth and try to decrease the area, the free-to-move conductor 2 will experience an electromagnetic force pushing it inward to contract the loop. Since it is on the right side, it must move to the left ($-\hat{i}$) to shrink the area! No cross products are required.

Answer 1

The Correct Option is A