Shows a circular wire-loop of radius a m carrying a current I, placed in a perpendicualr matgnetic field B. (a) Consider a small part dl of the wire. Find the force on this part of the wire exerted by the magnetic field. Find the force of compression in the wire.

Explanation

`F _(dl) = I , (dl xx B) = idLB
(because dl and B are perpndicular to each other )
` (b) 2T sin sin theta = I (dl xx B) `
`= I, 2a sin theta B `
` :. Sin theta is very small , sin sin theta = sin theta `
`2T sin theta = I , 2a sin theta B `
`:. T = iab`