Question

A circular loop of radius $0.0157m$ carries a current of $2.0amp$.The magnetic field at the center of the loop is
$({\mu }_o=4\pi \times {10}^{-7}weber/amp-m)$

• A. $1.57\times {10}^{-5}weber/m^2$
• B. $8.0\times {10}^{-5}weber/m^2$
• C. $2.5\times {10}^{-5}weber/m^2$
• D. $3.14\times {10}^{-5}weber/m^2$

Answer 1

The correct option is B $8.0\times {10}^{-5}weber/m^2$

The magnetic field due to a circular loop is given by:

$B=\frac{{\mu }_0}{4\pi }\frac{2\pi i}{r}$

$={10}^{-7}\times \frac{2\pi \times 2}{0.0157}$

$=8\times {10}^{-5}Wb/m^2$