A) At a point 10 cm from the stronger pole
B) At a point 20 cm from the stronger pole
C) At the mid-point
D) At infinity
Correct Answer: B
Solution :
Suppose magnetic field is zero at point P. Which lies at a distance x from 10 unit pole. Hence at P, \[\frac{{{\mu }_{0}}}{4\pi }\cdot \frac{10}{{{x}^{2}}}=\frac{{{\mu }_{0}}}{4\pi }\cdot \frac{40}{{{(30-x)}^{2}}}\,\,\,\,\Rightarrow \,\,\,x=10\,\,cm\] So from stronger pole distance is 20 cm.You need to login to perform this action.
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