Questions in Moving Charges and Magnetism

Select	Question
	The magnetic moment of a current (i) carrying circular coil of radius (r) and number of turns (n) varies as
	A current flows in a conductor from east to west. The direction of the magnetic field at a points above the conductor is .....
	A long wire carries a steady current. It is bent into a circle of one turn and the magnetic field at the centre of the coil is B. It is then bent into a circular loop of n turns. The magnetic field at the centre of the coil will be
	The magnetic field due to a current carrying circular loop of radius 3 cm at a point on the axis at a distance of 4 cm from the centre is $54 \mu T$. What will be its value at the centre of the loop
	The magnetic induction at the centre of a current carrying circular of coil radius r, is
	The current is flowing in south direction along a power line. The direction of magnetic field above the power line (neglecting earth's field) is
	Two wires of same length are shaped into a square and a circle. If they carry same current, ratio of the magnetic moment is
	When the current flowing in a circular coil is doubled and the number of turns of the coil in it is halved, the magnetic field at its centre will become
	An electron is revolving round a proton, producing a magnetic field of $16 weber/m^2$ in a circular orbit of radius 1Å. It’s angular velocity will be
	20 ampere current is flowing in a long straight wire. The intensity of magnetic field at a distance 10 cm from the wire will be