Advertisements
Advertisements
प्रश्न
Answer in brief.
For a very high-frequency AC supply, a capacitor behaves like a pure conductor. Why?
उत्तर
`"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
संबंधित प्रश्न
Obtain the expression for the emf induced in the rotating coil of N turns each of cross-sectional area A, in the presence of a magnetic field `vecB` .
State the principle on which the AC generator works. Draw a labelled diagram and explain its working.
State the working of a.c. generator with the help of a labeled diagram.
The coil of an a.c. generator having N turns, each of area A, is rotated with a constant angular velocity ω. Deduce the expression for the alternating e.m.f. generated in the coil.
What is the source of energy generation in this device?
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
The instantaneous values of alternating current and voltage in a circuit are
i = `1/sqrt2` sin 100π A and
v = `1/sqrt2 sin (100 pi"t" + pi/3)"V"`.
The average power in watts consumed in 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
Explain the working of a single-phase AC generator with necessary diagram.
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.
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)`
The north pole of a bar magnet is rapidly introduced into a solenoid at one end (say A). Which of the following statements correctly depicts the phenomenon taking place?
A resistor, capacitor, and inductor are connected in series across an AC generator. Which of the following statements is false?
The average e.m.f. produced in a coil, when a magnet is inserted into it does not depend upon
In an A.C circuit, the current
When the speed of a d.c. motor increases the armature current ______
The average value of alternating current over a full cycle is always ______. [I0 = Peak value of current]
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.
With the help of a labelled diagram, describe the principle and working of an ac generator. Hence, obtain an expression for the instantaneous value of the emf generated.
