A bar magnet has coercivity 
. It is desired to demagnetise it by inserting it inside a solenoid 12 cm long and having 60 turns. The current that should be sent through the solenoid is
Text Solution
Verified by ExpertsThe correct answer is:
D
The bar magnet coercively 
i.e., it requires a magnetic intensity 
to get demagnetized.
Let I be the current carried by solenoid having 
number of turns per metre length, then by definition 
.
Here 
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