Answer:
Distance of the null point from the centre of magnet \[d=14cm=0.14m.\] The earth's magnetic field where the angle of dip is zero, is the horizontal component of the earth's magnetic field. i.e. H = 0.36 G Initially, the null points are on the axis of the magnet. We use the formula of magnetic field on axial line (consider that the magnet is short in length). \[{{B}_{1}}=\frac{{{\mu }_{0}}}{4\pi }.\frac{2\,M}{{{d}^{3}}}\] This magnetic field is equal to the horizontal component of the earth's magnetic field. i.e. \[{{B}_{1}}=\frac{{{\mu }_{0}}}{4\pi }.\frac{2\,M}{{{d}^{3}}}=H\] ?(i) On an equatorial line of magnet at same distance (d), magnetic field due to the magnet \[{{B}_{2}}=\frac{{{\mu }_{0}}}{4\pi }.\frac{M}{{{d}^{3}}}=\frac{{{B}_{1}}}{2}=\frac{H}{2}\] ?(ii) The total magnetic field on equatorial line at this point (as given in question) \[B={{B}_{1}}+{{B}_{2}}=HI2+H\] \[=\frac{3}{2}H=\frac{3}{2}\times 0.36=0.54\,G\] The direction of magnetic field is in the direction of the earth's field.
You need to login to perform this action.
You will be redirected in
3 sec