Question

A current $i$ ampere flows in a circular arc of wire which subtends an angle $\frac{3 \pi}{2}$ radian at its center, whose radius is $R$. The magnetic field $B$ at its center is

• A. $\frac{\mu_{0} i}{R}$
• B. $\frac{3 \mu_{0} i}{2 R}$
• C. $\frac{3 \mu_{0} i}{4 R}$
• D. $\frac{3 \mu_{0} i}{8 R}$

Answer 1

Answer: (D)

$B=\frac{\mu_{0} i}{2 R}\left(\frac{3 \pi}{2(2 \pi)}\right)=\frac{3 \mu_{0} i}{8 R}$