One straight wire carries 5 A. Angles made by line segments joining point P at 10 cm on perpendicular bisector and the two ends of wire, with the wire are `60^(@)` each. Then magnetic field at this point will be ______ T.

Options

A. `3mu_(0)`
B. `3.98mu_(0)`
C. `39.8mu_(0)`
D. zero

Answer

B

Explanation

`B=(mu_(0)I)/(4piy)(cosalpha_(1)+cosalpha_(2))`
= `(mu_(0)xx5)/(4pixx0.1)[cos60^(@)+cos60^(@)]`
= `(50mu_(0))/(4xx3.14)[2cos60^(@)]=3.98089xx2xx1/2mu_(0)`
`thereforeB~~3.98mu_(0)T`