Question

The magnetic field at the centre ‘O’ in the given figure is

• A. $\frac{3}{10}\frac{\mu_{0}I}{R}$
• B. $\frac{7}{14}\frac{\mu_{0}I}{R}$
• C. $\frac{\mu_{0}I}{12R}$
• D. $\frac{5}{12}\frac{\mu_{0}I}{R}$

Answer 1

Answer: (D)

$\quad Here \, \theta =300^{\circ}$
$\therefore \, Number \,of \,turns\, n=\frac{300}{360}=\frac{5}{6}$
$B=\mu_{0} \frac{nI}{2R} i.e., \mu_{0} \frac{5}{6}\times\frac{I}{2 R}$
$\therefore \, B=\frac{5\mu_{0}I}{12 R}$