A) \[4\times {{10}^{-8}}\] tesla
B) \[3.5\times {{10}^{-8}}\] tesla
C) \[5\times {{10}^{-8}}\] tesla
D) \[3\times {{10}^{-8}}\]tesla
Correct Answer: C
Solution :
[c] Along the equatorial line, magnetic field strength \[B=\frac{{{\mu }_{0}}}{4\pi }\frac{M}{\left( {{r}^{2}}+{{\ell }^{2{{\,}^{3/2}}}} \right)}\] Given: \[M=4J{{T}^{-1}}\] r = 200cm = 2m \[\ell =\frac{6cm}{2}=3\,\,cm=3\times {{10}^{-2}}m\] \[\therefore \]\[B=\frac{4\pi \times {{10}^{-7}}}{4\pi }\times \frac{4}{{{\left[ {{2}^{2}}+{{\left( 3\times {{10}^{-2}} \right)}^{2}} \right]}^{3/2}}}\] Solving we get, B \[=5\times {{10}^{-8}}tesla\]You need to login to perform this action.
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