Question

Two parallel wire carries current $I_1$ and $I_2$ are separated by distance $d$. Force per unit length of wire is $F$.
Then :

• A. $F\propto d$
• B. $f\propto \frac{1}{d}$
• C. $F\propto d^2$
• D. $F\propto \frac{1}{d^2}$

Answer 1

The correct option is B $f\propto \frac{1}{d}$

Given : Two parallel wire carries current I1I1 and I2I2 are separated by distance dd. Force per unit length of wire is FF.

Solution:

We have the formula for force between two wires carrying current $I_{1}and{I}_2$

$\frac{dF}{dL}=\frac{\mu I_1{I}_2}{2\pi d}$

From here we can conclude that $f\propto \frac{1}{d}$

The Correct Opt=B