The flux linked with a coil at any instant t is given by \(\Phi\)_B = 10t² − 50t + 250. The induced emf at t = 3s is

In a transformer, the number of turns in the primary and the secondary are 410 and 1230 respectively. If the current in primary is 6A, then that in the secondary coil is

In an electrical circuit, R, L, C, and AC voltage source are all connected in series. When L is removed from the circuit, the phase difference between the voltage and current in the circuit is \(\frac{\pi}{3}\). Instead, if C is removed from the circuit, the phase difference is again \(\frac{\pi}{3}\). The power factor of the circuit is

An inductor 20 mH, a capacitor 50 μF and a resistor 40Ω are connected in series across a source of emf V = 10 sin 340 t. The power loss in AC circuit is

\(\frac{20}{\pi^2}H\)  inductor is connected to a capacitor of capacitance C. The value of C in order to impart maximum power at 50 Hz is

(a) Hysteresis loss
(b) Copper loss
(c) Flux loss
(d) Power loss

(a) Inductive reactance
(b) Self Inductance
(c) Capacitive reactance
(d) resistance

(I) : An AC generator converts electrical energy into mechanical energy.
(II) : A Transformer converts high voltage (low current) into low voltage (high current) and vice versa. Which one is incorrect statement?
(a) I only
(b) II only
(c) both are correct
(d) None

(I) In some AC generators, there are three separate coils, which would give three separate emfs. So they are called poly phase generator
(II) Eddy current loss can be minimised by using shell type core
Which one is correct statement?
(a) I only
(b) II only
(c) both are correct
(d) None

What is meant by electromagnetic induction?

State Lenz’s law.

Mention the ways of producing induced emf.

What is meant by mutual induction?

List out the advantages of stationary armature-rotating field system of AC generator.

Define average value of an alternating current.

A circular antenna of area 3 m² is installed at a place in Madurai. The plane of the area of antenna is inclined at 47^o with the direction of Earth’s magnetic field. If the magnitude of Earth’s field at that place is 4.1 x 10^–5 T find the magnetic flux linked with the antenna.

Give the uses of Foucault current.

Explain the construction and working of transformer.

Give the advantage of AC in long distance power transmission with an illustration.

The equation for an alternating current is given by i = 77 sin 314t. Find the peak current, frequency, time period and instantaneous value of current at t = 2 ms.

A square coil of side 30 cm with 500 turns is kept in a uniform magnetic field of 0.4 T. The plane of the coil is inclined at an angle of 30^o to the field. Calculate the magnetic flux through the coil.