Question

A circular coil of radius $11cm$, carries a current of $2.5A$. If it has $700$ turns, the flux density at the center of the coil is___

• A. $20mT$
• B. $10mT$
• C. $5mT$
• D. $0.1mT$

Answer 1

Answer: (B)

$10mT$

$B=\frac{n{\mu }_{0}i}{2r}$
$=\frac{700\times 4\pi \times {10}^{-7}\times 2\cdot 5}{2\times 11\times {10}^{-2}}$
$=10mT$