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A small flat search coil of area 5 cm^(2) with 140 closely wound turns is placed between the poles of a powerful magnet producing magnetic field 0.09 T and then quickly removed out of the field region. Calculate (a) change of magnetic flux through the coil, and (b) emf induced in the coil. |
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Answer» Solution :Here area of search COIL `A = 5 cm^(2) = 5 xx 10^(-4) m^(2)`, number of turns N = 140, magnetic field B = 0.09 T. (a) Initial magnetic FLUX `(phi_(B))_(i) = NBA = 140 xx 0.09 xx 5 x 10^(-4) = 6.3 xx 10^(-3)` Wb and final magnetic flux `(phi_(B)_(f) = 0. `therefore` Change of magnetic flux through the coil `Deltaphi_(B)=(phi_(B))_(i)-(phi_(B))_(f) = 6.3 xx 10^(-3)Wb` (b) If atime `Deltat` is SPENT in REMOVING the coil out of the magnetic field region, then magnitude of emf induced `|varepsilon| = (Deltaphi)/(Deltat) = (6.3 xx 10^(-3))/(Deltat)V` |
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