Question

A circular coil of radius $25cm$, carries a current of $50A$. If it has $35$ turns, the flux density at the centre of the coil is _______ $Wb/m^2$

• A. $\pi \times {10}^{-3}$
• B. $1.4\pi \times {10}^{-3}$
• C. $14\pi \times {10}^{-3}$
• D. $2\pi \times {10}^{-3}$

Answer 1

Answer: (B)

$1.4\pi \times {10}^{-3}$

$B=\frac{n{\mu }_{0}i}{2r}$
$=\frac{35\times 4\pi \times {10}^{-7}\times 50}{2\times 25\times {10}^{-2}}$
$=1\cdot 4\pi \times {10}^{-3}T$