(c) Given, inner radius and outer radius of toroid, r1=0.24,cm,r2=0.26m Current, I=10A Number of turns, N=2500 Number of turns per unit length of toroid, n=‌
N
2π(‌
r1+r2
2
)
=‌
2500
2π(‌
0.24+0.26
2
)
=‌
2500
2π×0.25
=‌
1×104
2Ï€
∴ Magnetic field inside the core of toroid, ‌B=µ0nI ‌=4π×10−7×‌