Electro- magnetism questions | form six Physics

Draw hysteresis loops diagram for soft iron and hard steel and use them to discuss permanent magnets.

Define permeability constant.

Derive an expression for the magnetic flux density B at the centre of the circular coil of radius r and N turns placed in air carrying a current I.

The diameter of a 40 turn circular coil is 16cm and it has a current of 5A. Calculate:

1. The magnetic induction at the centre of the coil.
2. The magnetic moment of the coil.
3. The torque acting on the coil if it is suspended in a uniform magnetic field of 0.76T such that its plane is parallel to the field.

Distinguish between self-inductance and mutual inductance.

A horizontal strainght wire of 0.05m long weighing 2.4gm^-1 is placed perpendicular to a uniform horizontal magnetic field of flux density 0.8T. If the resistance of the wire is 7.6m^-1, calculate the potential difference that has to be applied between the ends of the wire to make it just self-supporting.

Two very long wires made of copper and equal lengths are placed parallel to each other in such a way that they are 10cm apart. If the total power dissipated in the two wires is 75W, find the force between them if the resistivity of the copper wire is 1.69x10^-8m and a diameter of 2mm.

Explain the statement that, a sinusoidal current of peak value 5A passed through an a.c ammeter reads .

A coil which has an inductance of 0.2H and negligible resistance is in series in a resistor whose resistance is 60. The pair is connected across a 50V_emg supply alternating at . Calculate the total impendance of the circuit and its power factor.

State Lenz`s law of electromagnetic induction.