d
(d)From figure \({B_{net}} = \sqrt {{B_a}^2 + {B_e}^2} \)
\( = \sqrt {{{\left( {\frac{{{\mu _0}}}{{4\pi }}.\frac{{2M}}{{{d^3}}}} \right)}^2} + {{\left( {\frac{{{\mu _0}}}{{4\pi }}.\frac{M}{{{d^3}}}} \right)}^2}} \)
\( = \sqrt 5 .\frac{{{\mu _0}}}{{4\pi }}.\frac{M}{{{d^3}}}\)\( = \sqrt 5 \times {10^{ - 7}} \times \frac{{10}}{{{{(0.1)}^3}}}\)= \(\sqrt 5 \times {10^{ - 3}}\) \(Tesla\).
