Question

The radius of a circular loop is 0.4m and the current is 12A. What is the magnitude of magnetic field at the centre of the loop? $[Given{\mu }_0=4\pi \times {10}^{-7}Tm/A]$

• A. $1.66\times {10}^{-8}T$
• B. $21.66\times {10}^{-9}T$
• C. $32.45\times {10}^{-10}T$
• D. $18.86\times {10}^{-6}T$

Answer 1

The correct option is D $18.86\times {10}^{-6}T$

Magnetic field at the centre of circular loop is given by:
$B=\frac{{\mu }_{0}I}{2r}Here{\mu }_0=4\pi \times {10}^{-7}Tm/A;I=12A;r=0.4mSo,B=\frac{4\pi \times {10}^{-7}\times 12}{2\times 0.4}=6\pi \times {10}^{-6}=18.86\times {10}^{-6}T$