A current carrying wire AB of the length L is turned along a circle, as shown in figure. The magnetic field at the centre O.

Options

A. `(mu_(0)i)/(2R)((2pi-theta)/(2pi))^(2)`
B. `(mu_(0)i)/(2R)((2pi-theta)/(2pi))`
C. `(mu_(0)i)/(2R)(2pi-theta)`
D. `(mu_(0)i)/(2R)(2pi-theta)^(2)`

Answer

A

Explanation

`B=(mu_(0)i)/(4piR)(2pi-0)`
where,`(2pi-0)R=2piR`
`R'=(2piR)/(2pi-0) rArr B=(mu_(0)i)/(2R)((2pi-theta)/(2pi))^(2)`