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Derive an expression for the induced emf and induced current produced by changing the area of a rectangular coil placed perpendicular to a uniform magnetic field. |
Answer» Solution : CONSIDER a U-shaped conductor abcd LYING normal to a uniform magnetic field `vecB`. Let a conductor rod PQ is placed on frame abed and let it be moving with a uniform velocity `VECV`. As the rod MOVES by a small distance dx = v dt, the area enclosed changes from QcbP to Qʻcbp. Thus, change in magnetic FLUX `df_(B) = B(dA) = B [area QcbP to Q.cbP.]` = B (area Q.QPP.) = B l dx = B lvdt `therefore` magnitude for induced emf `|varepsilon| = (dphi_(B))/dt = (Blvdt)/dt = Blv` If R be the resistang of the loop then induced current `|I| = (|varepsilon|)/R = (Blv)/R.` |
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