Question

A symmetric star shaped conducting wire loop is carrying a steady state current $I$ as shown in the figure. The distance between the diametrically opposite vertices of the star is $4𝑎.$ The magnitude of the magnetic field at the center of the loop is

• A. $\frac{\mu_{o}I}{4\pi a}6\left[\sqrt{3}-1\right]$
• B. $\frac{\mu_{o}I}{4\pi a}6\left[\sqrt{3}+1\right]$
• C. $\frac{\mu_{o}I}{4\pi a}3\left[\sqrt{3}-1\right]$
• D. $\frac{\mu_{o}I}{4\pi a}3\left[2-\sqrt{3}\right]$

Answer 1

Answer: (A)

$B =12\left(\frac{\mu_{0} I }{4 \pi a }\right)(\sin 60-\sin 30)$