Force on Curved WireHardQuestion 20224
Question
A semi-circular wire of radius R lies in a plane perpendicular to a uniform field B. The net magnetic force on the wire when current I flows through it equals:
- AπIRB
- B2IRBCorrect
- CZero
- DIRB
Correct answer
2IRB
Explanation
The net force on any curved current in a uniform field equals ILB where L is the vector from start to end. For a semicircle, the chord length (straight-line distance between endpoints) = 2R, so F = I(2R)B = 2IRB. The net force is along the chord direction.