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

When the current changes from +2A to −2A in 0.05 s, an emf of 8 V is induced in a coil. The co-efficient of self-induction of the coil 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

A step-down transformer reduces the supply voltage from 220 V to 11 V and increase the current from 6 A to 100 A. Then its efficiency is

In a series resonant RLC circuit, the voltage across 100 Ω resistor is 40 V. The resonant frequency ω is 250 rad/s. If the value of C is 4 µF, then the voltage across L is

Give the principle of AC generator.

Define average value of an alternating current.

Write the application of series RLC resonant circut

When does the phenomenon of resonance is possibble in the circuit?

What is waltless current?

A cylindrical bar magnet is kept along the axis of a circular solenoid. If the magnet is rotated about its axis, find out whether an electric current is induced in the coil.

A closed coil of 40 turns and of area 200 cm², is rotated in a magnetic field of flux density 2 Wb m^–2. It rotates from a position where its plane makes an angle of 30^o with the field to a position perpendicular to the field in a time 0.2 s. Find the magnitude of the emf induced in the coil due to its rotation.

How does the capacitive reactance depend on frequency? & What is the reactance of a capacitor at hertz to the study at?

What is impedance? When does LCR circuit have minimum impedance?

Define power factor, what are the maximum and minimum values of power to circuit.

An inverter is common electrical device which we use in our homes. When there is no power in our house, inverter gives AC power to run a few electronic appliances like fan or light. An inverter has inbuilt step-up transformer which converts 12 V AC to 240 V AC. The primary coil has 100 turns and the inverter delivers 50 mA to the external circuit. Find the number of turns in the secondary and the primary current.

Write down the equation for a sinusoidal voltage of 50 Hz and its peak value is 20 V. Draw the corresponding voltage versus time graph.

In a LCR circuit, the voltage across an inductor, capacitor and resistance are 10V, 10V and 30V respectively, what is the phase difference between the applied voltage and the current in the circuit?

The instantaneous current and voltage of an a.c circuit are given by i = 10 sin 314t A and V = 50 sin (314t + π/2)V. What is the power dissipation in the circuit?