Write analogy between electrostatic and magnetism.
Physical quantity | Electrostatic | Magnetism |
$(1)$ Field | Electric field $\overrightarrow{\mathrm{E}}$ | Magnetic field $B$ |
$(2)$ Pole strength | Charge $(q)$ | Pole $\left(q_{\mathrm{m}}\right)$ |
$(3)$ Dipole moment | $p=q(2 a)$ | $m=q_{\mathrm{m}}(2 l)$ |
$(4)$ Constant | $\frac{1}{4 \pi \in_{0}}$ | $\frac{\mu_{0}}{4 \pi}$ |
$(5)$ Length of dipole | $2 a$ | $2 l$ |
$(6)$ Direction of dipole moment |
From negative charge to positive charge |
From south pole to north pole |
Write Gauss’s law for magnetism.
A charged particle (charge $q$) is moving in a circle of radius $R$ with uniform speed $v.$ The associated magnetic moment $\mu $ is given by
A magnetic needle suspended horizontally by an unspun silk fibre, oscillates in the horizontal plane because of the restoring force originating mainly from
A short bar magnet of magnetic movement $5.25 \times 10^{-2} \;J\, T ^{-1}$ is placed with its axis perpendicular to the earth's field direction. At what distance from the centre of the magnet, the resultant field is inclined at $45^{\circ}$ with earth's field on
$(a)$ its normal bisector and
$(b)$ its axis.
Magnitude of the earth's field at the place is given to be $0.42 \;G$. Ignore the length of the magnet in comparison to the distances involved.
If a piece of metal was thought to be magnet, which one of the following observations would offer conclusive evidence