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A conducting circular loop is placed is a uniform magnetic field B =0.20 T with its plane perpendicualr to the field . Somehow, the radius of the loop starts shrinking at a constant rate of `1.0 mm s^(-1)`. Find the induced emf in the loop at an instant when the radius is 2 cm. |
Answer» Here, `B = 0.02 T`, `(dr)/(dt) = 1.0 mm//s = 10^(-3) m // s` `e = ?, r = 2 cm = 2 xx 10^(-2) m` As `phi = BA = B (pi r^(2))` `:. |e| = (d phi)/(dt) = B (2 pi r) (dr)/(dt)` `0.02 xx 2 xx 3.14 xx 2 10^(-2) xx 10^(-3)` `= 2.5 xx 10^(-6) V` |
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