A cylindrical magnetic rod has length $$5 \mathrm{~cm}$$ and diameter $$1 \mathrm{~cm}$$. It has uniform magnetization $$5.3 \times 10^3 \mathrm{~A} / \mathrm{m}^3$$. Its net magnetic dipole moment is nearly

Two parallel wires of equal lengths are separated by a distance of $$3 \mathrm{~m}$$ from each other. The currents flowing through $$1^{\text {st }}$$ and $$2^{\text {nd }}$$ wire is $$3 \mathrm{~A}$$ and 4.5 A respectively in opposite directions. The resultant magnetic field at mid point between the wires $$\left(\mu_0=\right.$$ permeability of free space)

An electron is projected along the axis of circular conductor carrying current I. Electron will experience

The magnetic field at the centre of a circular coil of radius '$$R$$', carrying current $$2 A$$ is '$$B_1$$'. The magnetic field at the centre of another coil of radius '$$3 R$$' carrying current $$4 A$$ is '$$B_2$$'. The ratio $$B_1:B_2$$ is