Question

In a toroid the number of turns per unit length is $1000$ and current through it is $\frac{1}{4 \pi}$ ampere. The magnetic field produced inside (in weber/m $^{2}$ ) will be

• A. $10^{-2}$
• B. $10^{-3}$
• C. $10^{-4}$
• D. $10^{-7}$

Answer 1

Answer: (C)

$n=1000 $
$l=\frac{1}{4 \pi} A$
$B=\mu_{0} n i=4 \pi \times 10^{-7}(1000) \times \frac{1}{4 \pi}$
$B=10^{-4}( T )$