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How will you induce an emf by changing the area enclosed by the coil? Induction of emf by changing the area of the coil: |
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Answer» Solution :Consider a conductucing rod of length 1 moving with a velocity v towards left on a rectangular metallic framework as shown in Figure. The whole arrangement is placed in a uniform magnetic field `vec(B)` whose magnetic lines lines are perpendicular directed into the plane of the paper. ii. As the rod moves from AB to DC in a time date,the area enclosed by the loop and HENCE the magnetic flux through the loop decreases.  iii. The change in magnetic flux in time dt is `dPhi_(B)=Bxx"change in are"` `dPhi_(B)=Bxx"Area ABCD"` Blvdt Since area ABCD = l (vdt)``(or)(dPhi_(B))/(dt)=Blv` iv. As a result of change in flux, an emf is GENERATED in the loop. The magnitude of the induced emf is `epsilon=(dPhi_(B))/(dt)` `epsilon=Blv` v. This emf is called MOTIONAL emf. The direction of induced current is FOUND to be clockwise from Fleming's right hand rule. |
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