Question

Two parallel wires carrying same current I experience a force F. The graph which gives a straight line is

• A. $FversusI$
• B. $Fversus{I}^2$
• C. $F^{2}versusI$
• D. $Fversus{I}^{–1}$

Answer 1

The correct option is B $Fversus{I}^2$

Force per unit length acting between two parallel wires carrying same current I, separated at a distance r is given as:
$\frac{F}{L}=\frac{{\mu }_0{I}^2}{2\pi r}$
$\Rightarrow F\propto I^2[{\mu }_0,2\pi ,Iandrareconstants]$
Thus, the graph between F and $I^2$ will be a straight line.
Hence, the correct answer is option (2).