Question

A long solenoid of $100\text{cm}$ length having $100$ turns, carries a current of $5\text{A}$. The magnetic field at the end of the solenoid is : $({\mu }_0=4\pi \times {10}^{-7}{\text{T m A}}^{-1})$

• A. $3.14\times {10}^{-4}\text{T}$
• B. $3.14\times {10}^{-6}\text{T}$
• C. $6.28\times {10}^{-4}\text{T}$
• D. $6.28\times {10}^{-6}\text{T}$

Answer 1

The correct option is A $3.14\times {10}^{-4}\text{T}$

Magnetic field at end of the solenoid is given as
$B=\frac{{\mu }_{0}nI}{2}$
$\Rightarrow B=\frac{4\pi \times {10}^{-7}\times 100\times 5}{2}$
$\Rightarrow B=3.14\times {10}^{-4}\text{T}$