Question

Magnetic field at point $O$ due to the given structure is

• A. $\frac{{\mu }_{o}I}{4\pi R}(\frac{\pi }{2}+1)⨂$
• B. $\frac{{\mu }_{o}I}{4\pi R}(\frac{\pi }{2}+1)⨀$
• C. $\frac{{\mu }_{o}I}{2\pi R}(\frac{\pi }{2}+1)⨂$
• D. $\frac{{\mu }_{o}I}{2\pi R}(\frac{\pi }{2}+1)⨀$

Answer 1

The correct option is A $\frac{{\mu }_{o}I}{4\pi R}(\frac{\pi }{2}+1)⨂$

Direction of Magnetic field can be determined by Right hand screw rule and Finger rule:

$B_T=B_C+B_{w1}+B_{W2}$

$B_{W1}=0$ at axis

$B_{W2}=\frac{{\mu }_{o}I}{2\pi R}\times \frac{1}{2}$

$B_C=\frac{{\mu }_{o}I}{2R\times 4}$

$B_T=\frac{{\mu }_{o}I}{4\pi R}(\frac{\pi }{2}+1)⨂$