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 11A, what is the magnetic field (a) outside the toroid? (b) inside the core of the toroid? (c) in the empty space surrounded by the toroid?

Explanation

Mean radius of the toroid `=(0.25+0.26)/2=0.255m`
`N=3500, I=11A, n=N/(2pir)=(3500)/(2 times 3.142 times 0.2555)`
i.e., `" "`n = 2184.196
(a) Magnetic field outside the toroid is zero.
(b) Magnetic field inside the core of the toroid,
`" "B=mu_(0)nI=4 times 3.142 times 10^(-7) times 2184.196 times 11T`
`" "=3.02 times 10^(-2)T.`
(c) In the empty space surrounded by the toroid, magnetic field = 0