A toroid has a core (non ferromagnetic material) of inner radius `25cm` and outer radius `26cm` 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?

Options

A. `(0,0,3xx10^(-2)T)`
B. `(0,0,0)`
C. `(0,3xx10^(-2)T,0)`
D. `(3xx10^(-2)T,0,3xx10^(-2)T)`

Answer

3

Explanation

Total turns in the toroid are given 3500.
`(a)` Outside the toroid the magnetic field is zero.
`(b)` Inside the core of toroid, the magnetic field will be
`B= mu_(0)nl" " B=mu(N)/(2pir)I`
Here `r` can be taken mean of inner and outer radius `i.e., 25.5cm`.
So, `B=(4pixx10^(-7))/(2pi)(3500xx11)/(25.5xx10^(-2))=3xx10^(-2)T`
`(c)` Magnetic field in the empty space surrounded by the torroiod is also zero.