Question

A long solenoid has $800$ turns per metre length of solenoid. A current of $1.6\text{A}$ flows through it.

$\left(i\right)$ Find the value of magnetic field at the end of the solenoid on its axis.

​​​​​​​$[$1 Mark$]$

• A. $16\times {10}^{-4}\text{T}$
• B. $8\times {10}^{-4}\text{T}$
• C. $32\times {10}^{-4}\text{T}$
• D. $4\times {10}^{-4}\text{T}$

Answer 1

The correct option is B $8\times {10}^{-4}\text{T}$

Magnetic field at the end of the solenoid on its axis is given by,
$B=\frac{{\mu }_{0}ni}{2}$

$B=\frac{4\pi \times {10}^{-7}\times 800\times 1.6}{2}=8\times {10}^{-4}\text{T}$