The cartesian equation of the line passing through (4, 9, 8) and (3, - 2, 1) is ..

Options

A. `I_(1),I_(2)` negative and `I_(3),I_(4)` positive
B. `I_(1),I_(2)` positive and `I_(3),I_(4)` negative
C. `I_(1),` positive and `I_(2),I_(3),I_(4)` negative
D. `I_(1),I_(4),I_(3)` positive and `I_(2)` negative

Answer

B

Explanation

When right handed screw, placed perpendicular to given planar loop (enclosing some currents) is rotated in the same sense as that of line integration over the given loop, current in the direction of advancement of right handed screw is to be taken positive and current in the opposite direction is to be taken negative.
As per above convention, `I_(1)andI_(2)` are positive whereas `I_(3)andI_(4)` are negative.