The centres of the turns of a toroid form a circle with a radius of 14.0 cm. The cross-sectional area of each turn is `3.00 cm^(2)` . It is wound with 5278 turns of fine wire, and the wire carries a current of `4.00 A`. The core is filled with a paramagnetic material of magnetic susceptibility `2.90 xx 10^(–4)`. What would the magnitude of the magnetic field within the substance ?

Options

A. 12.08 mT
B. 30.16 mT
C. 10.6 mT
D. 16.6 mT

Answer

B

Explanation

The magnetic field due to a toroid is
`B = (mu_0 NI)/(2piR)`
`implies B = (4pi xx10^(-7)xx5278xx4)/(2pixx14xx10^(-2))=3016 xx10^(-5)T`