AP EAPCET 25-Aug-2021 Shift 1 Paper

Given, inner radius, r1=20‌cm=0.2m
Outer radius, r2=25cm=0.25m
Number of turns, N=800
Current in the toroid, I=12A
Magnetic field due to N circular rings ( coroid),
B=

µ.NI

2πr

Magnetic field is maximum at rmin=0.2m
Bmax=

4π×10−7×800×12

2π(0.2)

=9.6×10−3T
=9.6‌mT
Magnetic field is minimum at rmax=0.25m
Bmin=

4π×10−1×800×12

2π×(0.25)

=7.68×10−3T
=7.68‌mT
So, the maximum value of magnetic field within the toroid is 9.6‌mT and minimum value of magnetic field within the toroid is 7.68‌mT.