The current in the wire is `I`. The current comes from infinite parallel to `z`-axis and finally goes to finite paralle to `y`-axis as shown in the figure. Find magnetic field `O` in vector from for the following current configurations.

Options

A. `(mu.I)/(2piR)[hatj+((2+7pi))/4(-hatk)]`
B. `(mu.I)/(4piR)[hatj+((2+7pi))/4(hatk)]`
C. `(mu.I)/(4piR)[hatj+((2+7pi))/4(-hatk)]`
D. None of these

Answer

C

Explanation

`vecB=(mu_(0)1)/(4piR) hatj-(mu_(0)I)/(4piR) (3pi)/3 hatk-(mu_(0))/(4pi)(I/(2R)) pi/2 hatk`
`-(mu_(0))/(4pi) I/(2R) hatk=(mu_(0)I)/(4piR)[hatj-((7pi+2))/4hatk]`