A current I flowing through the loop as shown in figure. The magnetic field at centre O is

Options

A. `(7mu_(0) I)/(16 R) "" otimes`
B. `(7 mu_(0) I)/(16 R) "" odot`
C. `(5 mu_(0) I)/(16 R) "" otimes `
D. `(5 mu_(0)I)/(16 R) "" odot`

Answer

A

Explanation

`B = B_(EP) + B_(RS)` (into the paper )
`= (mu_(0))/(4pi) xx (3 pi I)/(2R) + (mu_(0))/(4pi) xx (pi)/(2) xx (I)/(2 R) = (7)/(16) (mu_(0) I)/( R)`