A current of 5 A flows in a square loop of side 1 m placed in air. The magnetic field at the centre of the loop is X 2 10-7 T. The value of X is .
40
Each side: finite wire at distance d= a2=0.5 m, ends subtending 45 on each side
B=4 0I4 d( 45 + 45 )
=4 10-7 50.5 2
=40 2 10-7 T
X=40
Answer: 40
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