A square frame carrying a current I is located in the same plane as a long straight wire carrying a current `I_(0)` The frame side has a length a. The axis of the frame passing through the midpoints of the opposite sides is parallel to the wire and is separated from it by the distance which is `eta` times greater than the side of the frame. Find

(a) Force acting on the frame
(b) The mechanical work to be performed in order to turn the frame through `180^(@)` about its axis, with the currents maintained constant.