Question

An infintely long straight wire is carrying a current $I_1$.Adjacent to it there is another equilateral triangular wire having current $I_2$.Choose the wrong options.

• A. Net force on loop is leftwards
• B. Net force on loop is rightwards
• C. Net force on loop is upwards
• D. Net force on loop is downwards

Answer 1

Answer: (A), (B), (C), (D)

The correct options are
A Net force on loop is leftwards
B Net force on loop is rightwards
C Net force on loop is upwards
D Net force on loop is downwards

Magnetic Force on a conductor = $i\overline{l}\times \overline{B}$

wires having current in same direction attract and those with opposite repel.

Let's observe these above.

force on AB by $I_1$ is mostly attractive in nature. and on BC is repulsive.

But the field strength are different over these two conductors. $|F_{AB}|>|F_{BC}|$ in magnitude.

Hence laterally the net force is towards left. But we must also consider vertical force. Closed loops with current in one sense(cw or acw) don't have vertical net force. Always cancels out. vertical upward force on ABC = vert. downward force on AC

Thus, net force is towards left.