Question

Four parallel conductors, carrying equal currents, pass vertically through the four corners of a square WXYZ. In two conductors, the current is flowing into the page, and in the other two out of the page. In what directions must the current flow to produce a resultant magnetic field in the direction shown at $O$, the center of the square?

• A. Into the page= W and Y; Out of the page =X and Z
• B. Into the page= X and Z; Out of the page =W and Y
• C. Into the page= W and Z; Out of the page =X and Y
• D. Into the page= W and X; Out of the page =Y and Z

Answer 1

The correct option is D Into the page= W and X; Out of the page =Y and Z

The direction of magnetic field at O due to,

1. W into the plane is along OZ.

2. X into the plane is along OW.

3. Y out of the plane is along OZ.

4. Z out of the plane is alon OW.

Since field due to each of them would have equal magnitudes being equidistant from the point O, the net field would be along the given direction.