JEE Main | 2014ElectroMagnetic InductionHard
Question
The coercivity of a small magnet where the ferromagnet gets demagnetized is 3 × 103 A m-1. The current required to be passed in a solenoid of length 10 cm and number of turns 100, so that the magnet gets demagnetized when inside the solenoid, is
Options
A.30 mA
B.60 mA
C.3 A
D.6 A
Solution
B = μ0 n i
= ni (n= number of turns per unit length)
3 × 103 =
I = 3 A.
= ni (n= number of turns per unit length)3 × 103 =
I = 3 A.
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