A current loop, having two circular arcs jo ined by two radial lines is shown in the figure. It carries a current of 10 A. The magnetic field at point O will be close to :

Options

A. `1.0xx10^(-7)T`
B. `1.0xx10^(-5)T`
C. `1.5xx10^(-7)T`
D. `1.5xx10^(-5)T`

Answer

B

Explanation

Magnetic field due to sections PQ & RS at O is zero.

`:.` Net magnetic field at `O=(mu_(0)Itheta)/(4pi)[1/(3cm)-1/(5cm)]`
`=10^(-7)xx10xx(pi)/4[100[1/3-1/5]]`
`=10^(-4)xx(pi)/4xx2/15=(pi)/30xx10^(-4)`
`~~1xx10^(-5)T` i.e. option B