Moving Charges ...

The earth\'s magnetic induction at certain point is 7 × 10^–5 Wb/m². This is to be annulled by the magnetic induction at the centre of a circular conducting loop of radius 5 cm. The required current in the loop is

A straight wire carrying a current 10 A is bent into a semicircular arc of radius 5 cm. The magnitude of magnetic field at the centre is

An electric current passes through a long straight wire. At a distance 5 cm from the wire, the magnetic field is B. The field at 20 cm from the wire would be

When a certain length of wire is turned into one circular loop, the magnetic induction at the centre of coil due to some current flowing is B₀. If the same wire is turned into three loops to make a circular coil, the magnetic induction at the centre of this coil for the same current will be

The current in the windings on a toroid is 2.0 A. There are 400 turns and the mean circumferential length is 40 cm. If the inside magnetic field is 1.0 T, the relative permeability is near to

A long solenoid carrying a current produces a magnetic field B along its axis. If the current is doubled and the number of turns per cm is halved, the new value of the magnetic field is

The earth\'s magnetic field at a given point is 0.5 × 10^–5 Wb-m^–2. This field is to be annulled by magnetic induction at the center of a circular conducting loop of radius 5.0 cm. The current required to be flown in the loop is nearly

The magnetic moment of a current (i) carrying circular coil of radius (r) and number of turns (n) varies as

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

The field due to a long straight wire carrying a current I is proportional to