Question

A solenoid $3.142m$ long and $5.0cm$ in diameter has two layers of windings of $500$ turns each and carries a current of $5A$. Calculate the magnetic induction at its centre along the axis.

Answer 1

Given : Length $=3.14m$

$d=5.0cm$

or $r=2.5\times {10}^{-2}m$

$i=5A$

No. of turns $=500\times 2$

$=1000$

Magnetic induction at the centre,

$B=\frac{{\mu }_{0}Ni}{l}$

$=\frac{4\pi \times {10}^{-7}\times 500\times 2\times 5}{3.14}$

$=\frac{4\times 3.14\times {10}^{-7}\times 5000}{3.14}$

$=2.0\times {10}^{-3}T$.