Question

A solenoid of length $50cm$ with $600turns$ is connected to a cell and current through the solenoid is $\frac{20}{\pi }A$. Find magnetic field inside the solenoid (in central region). Assume solenoid is ideal

• A. $9.6\times {10}^{-3}T$
• B. $4.8\times {10}^{-3}T$
• C. $2.4\times {10}^{-3}T$
• D. $9.6\times {10}^{-7}T$

Answer 1

The correct option is A $9.6\times {10}^{-3}T$

$B={\mu }_{o}ni$
$n=\frac{N}{l}=\frac{600}{0.5}=1200$
$i=\frac{20}{\pi }$
$B=4\pi \times {10}^{-7}\times 1200\times \frac{20}{\pi }$
$=9.6\times {10}^{-7}$
$=9.6\times {10}^{-3}T$