Question

how would the strength of magnetic field produced at the centre of a circular loop be affected if

a) the strength of current passing through the loop is doubled?

b) the radius of this loop is reduced to one half of the original radius?

Answer 1

The value of magnetic field at the centre of the circular coil of radius r with n number of turns of wire carrying current I is given by the expression :
$B=\frac{{\mu }_0}{4\pi }\frac{I}{r}\times 2\pi n$
where, ${\mu }_{0}isabsolutemagneticpermeabilityoffreespace.$
1. If strength of current passing through the coil is doubled,then magnetic field will also get double as magnetic field is directly proportional to current.
2. if radius of the coil is halved, then also the magnetic field will get doubled.