Question

Figure 4.40 shows two
semicircular loops of
radii Rand Ry carrying
current I. Find the magni-
tude and direction of the
magnetic field at the
common centre O.​

Answer 1

ANSWER

Here the field due to "SR" and "OQ" will be zero because they pass through point "O" and intersect each other. The field is only present due to wires have radii "R1​" and "R2​".


so, we know that field due to semi-circular current(B)=4Rμi​.


for semi-circle have radius R1​=4R1​μi​


for semi-circle have radius R2​=4R2​μi​.


on adding both we find our final result,i.e


Bnet​=4μi​×[R1​1​+R2​1​].