A toroid has a non-ferromagnetic core of inner radius 25 cm and outer radius 26 cm, around which 350

Question

A toroid has a non-ferromagnetic core of inner radius 25 cm and outer radius 26 cm, around which 3500 turns of wire are wound. If the current in the wire is 11 A, what is the magnetic field inside the core of the toroid?

Professor PC Thomas Classes · Answer

Mean radius $r = \frac{25+26}{2} = 25.5	ext{ cm} = 0.255	ext{ m}$. $B = \frac{\mu_0 N I}{2\pi r} = \frac{4\pi 	imes 10^{-7} 	imes 3500 	imes 11}{2\pi 	imes 0.255} \approx 3.0 	imes 10^{-2}	ext{ T}$.