Find the force experienced by a semicircular rod having a charge q as shown in fig. Radius of the wire is R, and the line of charge with linear charge density `lambda` passes through its center and is perpendicular to the plane of wire.

Answer

B

Explanation

`dF=(dq)(lambda/(2pi in_(0)R))=((qdtheta)/pi)(lambda/(2pi in_(0)R))`
`F_("net")=underset(0)overset(pi//2)(int)2dF cos theta=(qlambda)/(pi^(2) in_(0)R)`
`rArr underset(0)overset(pi//2)(int) cos theta d theta=(qlambda)/(pi^(2) in_(0)R)`