A) \[\frac{B}{6}\]
B) \[\frac{B}{4}\]
C) \[\frac{B}{3}\]
D) \[\frac{B}{2}\]
Correct Answer: B
Solution :
The magnetic field at a distance r from the straight wire \[B=\frac{{{\mu }_{0}}i}{2\pi r}\] or \[B\propto \frac{1}{r}\] or \[\frac{{{B}_{2}}}{{{B}_{1}}}=\frac{{{r}_{1}}}{{{r}_{2}}}\] \[\therefore \] \[\frac{{{B}_{2}}}{B}=\frac{5}{20}=\frac{1}{4}\] or \[{{B}_{2}}=\frac{B}{4}\]You need to login to perform this action.
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