KCET 2020 Physics Solved Paper

Magnetic field at the center of the current carrying loop is given by B=

µ0

4π

×

2πi

a

=

µ0i

2a

.
Magnetic moment at the center of the current carrying loop is given by M=iπa2 thus

B

M

=

µ0

2πa3

=x (given) when both current and radius are doubled ratio become

x

8

times.