Evaluate magnitude and direction of magnetic field at a point P in the following cases

`

Options

A. (i),(ii)
B. (ii),(iii)
C. (i),(iii)
D. all

Answer

D

Explanation

(i)
`R_(1)=(2R_(0))/3, R_(2)=(R_(0))/3`
`i_(1)=(R_(2))/(R_(1)+R_(2))=i/3, i_(2)=i-i_(1)=2i//3`
`B_(1)=(mu_(0)i_(1))/(2R).2/3=(mu_(0)i)/(9R),ox`
`B_(2)=(mu_(0)i_(2))/(2R).1/3=(mu_(0)i)/(9R),o.`
`B_(O)=B_(1)-B_(2)=0`
(ii)
`B_(O)=0`
(iii)
`B_(O)=0`