The coercitivity of a small magnet where the ferromagnet gets demagnetized is `3 xx 10^(3) Am^(-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 :
A
` 30 mA`
B
` 60 mA`
C
`3 A`
D
` 6 A`
Text Solution
Verified by Experts
The correct Answer is:
C
Magnetic field in solenoid `B = mu_(0) n I ` rArr `(B)/( mu_(0)) = ni` ( where n = number of turns per unit length) rArr `(B)/( mu_(0)) = (ni)/(L)` rArr ` 3 xx 10^(3) = ( 100 i)/( 10 xx 10^(-2))` ` I = 3 A`
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