## In This post you will get answer of Q.

The inner and outer radius of a toroid core are $28 ,cm$ and $29, cm$ respectively and around the core $3700$ turns of a wire are wounded. If the current in the wire is $10, A$, then the magnetic field inside the core of the toroid is

Solution:

## The number of turns per unit length for the given toroid $n=frac{N}{2pi r_{av}}$

The average radius of toroid

$r_{av}=frac{28+29}{2}=28.5,cm$

$=28.5times10^{-2},m$

$therefore n=frac{3700}{2times3.14times28.5times10^{-2}}$

$=2067.27 approx2067$

Now, $B=mu_{0}nI=4pitimes10^{-7}times2067times10$

$=259615.2times10^{-7}, T $

$=2.60times10^{-2}, T$