Advertisements
Advertisements
Question
Answer in brief.
For a very high-frequency AC supply, a capacitor behaves like a pure conductor. Why?
Solution
`"X"_"C" = 1/(2pi"fC")` is the reactance of a capacitor, where f is the frequency of the AC supply and C is the capacitance of the capacitor. For extremely high frequencies, f, XC is extremely small. As a result, for a very high-frequency alternating current supply, a capacitor behaves like a pure conductor.
APPEARS IN
RELATED QUESTIONS
Suppose the loop is stationary but the current feeding the electromagnet that produces the magnetic field is gradually reduced so that the field decreases from its initial value of 0.3 T at the rate of 0.02 T s−1. If the cut is joined and the loop has a resistance of 1.6 Ω how much power is dissipated by the loop as heat? What is the source of this power?
Draw a labelled diagram of an ac generator.
State the principle of an ac generator and explain its working with the help of a labelled diagram. Obtain the expression for the emf induced in a coil. having N turns each of cross-sectional area A, rotating with a constant angular speed 'ω' in a magnetic field `vecB` directed perpendicular to the axis of rotation.
Describe briefly, with the help of a labelled diagram, the basic elements of an A.C. generator.
State A.C. generator underlying principle?
In an electrical circuit, R, L, C, and AC voltage sources are all connected in series. When L is removed from the circuit, the phase difference between the voltage and current in the circuit is `π/3`. Instead, if C is removed from the circuit, the phase difference is again `π/3`. The power factor of the circuit is
`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
Define average value of an alternating current.
Elaborate the standard construction details of AC generator.
How are the three different emfs generated in a three-phase AC generator? Show the graphical representation of these three emfs.
A flexible metallic loop abcd in the shape of a square is kept in a magnetic field with its plane perpendicular to the field. The magnetic field is directed into the paper normally. Find the direction of the induced current when the square loop is crushed into an irregular shape as shown in the figure.
In an A.C. circuit, the peak value of voltage is 320 volt. Its effective voltage is ______
An alternating e.m.f. is given by e = e0 sin ωt. In what time the e.m.f. will have half its maximum value, if 'e' starts from zero? (T = Time period)
`(sin 30^circ = cos 60^circ = 0.5, cos 30^circ = sin 60^circ = sqrt3/2)`
When the plane of the armature of a generator is parallel to the field. in which it is rotating ______.
A resistor, capacitor, and inductor are connected in series across an AC generator. Which of the following statements is false?
The angular frequency of a.cat which a coil of inductance 1 m H has a reactance of l Ω is
The average e.m.f. produced in a coil, when a magnet is inserted into it does not depend upon
The coil of an ac generator consists of 100 turns of wire, each of area 0.5 m2. The resistance of the wire is 100 Ω. The coil is rotating in a magnetic field of 0.8 T perpendicular to its axis of rotation, at a constant angular speed of 60 radians per second. Calculate the maximum emf generated and power dissipated in the coil.
Briefly describe the working of ac generator.
Obtain the expression for the instantaneous value of emf induced.
