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The coercivity of a certain permanent ma...

The coercivity of a certain permanent magnet is `4*0xx10^4Am^-1`. This magnet is placed inside a solenoid `15cm` long and having `600turns`. Calculate the current required to demagnetise the magnet completely.

Text Solution

Verified by Experts

Here, coercivity `=4*0xx10^4Am^-1` of magnet implies that magnetising intensity `H=4*0xx10^4Am^-1` is required to be applied in opposite direction to demagnetise the magnet.
n=number of turns per unit length
`=(600)/(15xx10^-2)=4000turns//m`
As `H=nI :. I=H/n=(4*0xx10^4)/(4000)=10A`
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