A) \[{{\mu }_{0}}i/2\pi r\]
B) \[{{\mu }_{0}}{{i}^{2}}/{{r}^{2}}\]
C) \[{{\mu }_{0}}{{i}^{2}}/2\pi r\]
D) \[{{\mu }_{0}}i/{{r}^{2}}\]
Correct Answer: C
Solution :
When a wire is placed in a magnetic field\[B\], carrying current\[i\], separated by a distance\[r\]from another wire carrying the same current, then magnitude of force\[(F)\]is \[F=iBl=i\left( \frac{{{\mu }_{0}}}{2\pi }\frac{i}{r} \right)l\] Force per unit length\[\frac{F}{l}=\frac{{{\mu }_{0}}}{2\pi }\frac{{{i}^{2}}}{r}\] When currents are in same direction, then from Flemings left hand rule, force of attraction acts between them.You need to login to perform this action.
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