A) 2 A
B) 4 A
C) 6 A
D) 8 A
Correct Answer: D
Solution :
The bar magnet coercivity \[4\times {{10}^{3}}A{{m}^{-1}}\]i.e., it requires a magnetic intensity \[H=4\times {{10}^{3}}A{{m}^{-1}}\]to get demagnetised. Let i be the current carried by solenoid having n number of turns per metre length, then by definition H = ni. Here \[H=4\times {{10}^{3}}\]Amp turn metre-1 \[n=\frac{N}{l}=\frac{60}{0.12}=500\] turn metre?1 \[\Rightarrow i=\frac{H}{n}=\frac{4\times {{10}^{3}}}{500}=8.0\ A\]You need to login to perform this action.
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