Advertisements
Advertisements
प्रश्न
An AC source rated 100 V (rms) supplies a current of 10 A (rms) to a circuit. The average power delivered by the source
(a) must be 1000 W
(b) may be 1000 W
(c) may be greater than 1000 W
(d) may be less than 1000 W
उत्तर
(b) may be 1000 W
(d) may be less than 1000 W
The average power delivered by an AC source is given by,
`P_{avg} = V_{rms}I_rms cos Ø`
Given ;
`V_rms = 100V`
`Irms = 10 A`
⇒ `P_{avg} = 1000 cos `Ø
`therefore Ø ∈ (-pi/2, pi/2)`
⇒ cos Ø ∈ (0,1),
`therefore 0 ≤ P_{avg] ≤ 1000`
APPEARS IN
संबंधित प्रश्न
An a.c. source of voltage V = V0 sin ωt is connected to a series combination of L, C, and R. Use the phasor diagram to obtain the expression for an impedance of a circuit and the phase angle between voltage and current. Find the condition when current will be in phase with the voltage. What is the circuit in this condition called?
When an AC source is connected to an ideal inductor show that the average power supplied by the source over a complete cycle is zero.
Ajit had a high tension tower erected on his farm land. He kept complaining to the authorities to remove it as it was occupying a large portion of his land. His uncle, who was a teacher, explained to him the need for erecting these towers for efficient transmission of power. As Ajit realised its significance, he stopped complaining.
Answer the following questions:
(a) Why is it necessary to transport power at high voltage?
(b) A low power factor implies large power loss. Explain.
(c) Write two values each displayed by Ajit and his uncle.
A lamp is connected in series with an inductor and an AC source. What happens to the brightness of the lamp when the key is plugged in and an iron rod is inserted inside the inductor? Explain.
Prove theoretically the relation between e.m.f. induced in a coil and rate of change of magnetic flux in electromagnetic induction.
Define the quality factor in an a.c. circuit. Why should the quality factor have high value in receiving circuits? Name the factors on which it depends.
In a circuit, containing a capacitor and an AC source, the current is zero at the instant the source voltage is maximum. Is it consistent with Ohm's Law?
A resistance is connected to an AC source. If a capacitor is included in the series circuit, will the average power absorbed by the resistance increase or decrease? If an inductor of small inductance is also included in the series circuit, will the average power absorbed increase or decrease further?
In an AC series circuit, the instantaneous currt is zero when the instantaneous voltage is maximum. Connected to the source may be a
(a) pure inductor
(b) pure capacitor
(c) pure resistor
(d) combination of an inductor and a capacitor
What is the value of power factor for a pure resistor connected to an alternating current source ?
In previous questions 3 and 4, what is the net power absorbed by each circuit over a complete cycle. Explain your answer.
The power factor in a circuit connected to an A.C. The value of power factor is ______.
The series combination of R, L, C is connected to an a.c. source. If the resistance is 3 and the reactance is 4, the power factor of the circuit is:
In the series LCR circuit, the power dissipation is through ______
An alternating current generator has an internal resistance Rg and an internal reactance Xg. It is used to supply power to a passive load consisting of a resistance Rg and a reactance XL. For maximum power to be delivered from the generator to the load, the value of XL is equal to ______.
