NEET-XII-Physics
36: Permanent Magnets
- #1A long bar magnet has a pole strength of 10 Am. Find the magnetic field at a point on the axis of the magnet at a distance of 5 cm from the north pole of the magnet.Ans : Given:
Pole strength of the bar magnet, m = 10 Am
Distance of the point from the north pole of the bar magnet, r = 5 cm = 0.05 m
We know,
The magnetic field due to magnetic charge `` \left(B\right)`` is given by
`` B=\frac{{\,\mathrm{\,\mu \,}}_{0}}{4\,\mathrm{\,\pi \,}}\frac{m}{{r}^{\mathit{2}}}``
`` =\frac{{10}^{-7}\times 10}{{\left(5\times {10}^{-2}\right)}^{2}}=\frac{{10}^{-6}}{25\times {10}^{-4}}``
`` =\frac{{10}^{-2}}{25}=4\times {10}^{-4}\,\mathrm{\,T\,}``
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