A quantity which varies sinusoidally with time and represented as the projection of a rotating vector is called phasor.

(i) As the plate oscillate, the changing magnetic flux through the plate produces a strong eddy current in the direction, which opposes the cause.
(ii) Also copper being diamagnetic substance, it gets magnetised in the opposite direction, so the motion of copper plate is stopped.

If the loop moves within the region of a uniform magnetic field no current will be induced in the loop. Hence no direction.

The current in the coil will flow clockwise the direction of current will be from P to Q in coil PQ and from C to D in coil CD.

Lenz's law the polarity of the induced emf is such that it tends to produce current which oppose the change in magnetic flux that produces it.

The phenomenon of electrical resonance is possible when the circuit contains both L and C. Only then does the voltage across L and C cancels one another when VL and VC are 1800 out of phase and the circuit becomes purely resistive. This implies that resonance will not occur in RL and RC circuits.

The magnetic flux through an area A in a magnetic field is defined as the number of magnetic field lines passing through that area normally and is given by the equation.
\({ \Phi }_{ B }=\int _{ A }^{ }{ \vec { B } .d\vec { A } =BAcos\theta } \)
where the integral is taken over the area A and θ is the angle between the direction of the magnetic field and the outward normal to the area.

Whenever energy is given to a circuit containing a pure indicator L and a capacitor of capacitance C, the energy oscillates back and fourth between the magnetic field of the indicator and the electric field of the capacitor. Thus the electrical oscillations of definite frequency are generated. these oscillations are called LC oscillations.

The current in an AC circuit is said to be wattless current if the power consumed by it is zero.

Resonant frequency is the frequency of the applied alternating source at which the current in the circuit reaches its maximum value.

(i) The current is drawn directly from fixed terminals on the stator without the use of brush contacts.
(ii) The insulation of stationary armature winding is easier.
(iii) The number of sliding contacts (slip rings) is reduced. Moreover, the sliding contacts are used for low-voltage DC Source.
(iv) Armature windings can be constructed more rigidly to prevent deformation due to any mechanical stress.

AC generator work on the principle of electromagnetic induction. The relative motion between a conductor and a magnetic field changes the magnetic flux linked with the conductor which in turn, induces an emf

Emf can be produced by changing magnetic flux in any of the following ways:
(i) By changing the magnetic field B
(ii) By changing the area A of the coil and
(iii) By changing the relative orientation θ of the coil with magnetic field.

Even for a conductor in the form of a sheet or plate, an emf is induced when magnetic flux linked with it changes. But the difference is that there is no definite loop or path for induced current to flow away. As a result, the induced currents flow in concentric circular paths. As these electric currents resemble eddies of water, these are known as Eddy currents. They are also called Foucault currents.