Describe the nature of the magnetic field as connected with nature of current.

If a long copper rod carries a direct current, the magnetic field associated with the current will be

Draw the pattern of magnetic field lines around a current carrying straight conductor.How does the strength of magnetic field produce change with an increase in current in a conductor?

Derive an expression for the magnetic field.at the centre of a current carrying coil.

Derive an expression for magnetic field at the centre of circular current carrying coil.