A thin flexible wire of length L is connected to two adjacent fixed points and carries a current I in the clockwise direction, as shown in the figure. When the system is put in a uniform magnetic fiel

Question

A thin flexible wire of length L is connected to two adjacent fixed points and carries a current I in the clockwise direction, as shown in the figure. When the system is put in a uniform magnetic field of strength B going into the plane of the paper, the wire takes the shape of a circle. The tension in the wire is

TestHub · Accepted Answer

L = 2 π R R = 2 π L ​ 2 T sin ( d θ ) = F m ​ for small angles, sin ( d θ ) ≈ d θ ∴ 2 T ( d θ ) ∴ T ​ = I ( d L ) B sin 9 0 ∘ = I ( 2 R ⋅ d θ ) ⋅ B = I RB = 2 π I L B ​ ​ ∴ correct option is (c)

Physics - Magnetism Question with Solution | TestHub

Options:

Doubts & Discussion

JEE Main (2026)