Advertisements
Advertisements
प्रश्न
Can you have an AC series circuit in which there is a phase difference of (a) 180° (b) 120° between the emf and the current?
उत्तर
Let us consider an AC series LCR circuit of angular frequency ω. The impedance of the circuit is given by,
`Z =sqrt(R^2 + (omegaL - 1/(omegaC))`
The phase difference between V and I is given by,
`tan Ø = (omegaL - 1/(omegaC))/Z`
From the above formula, we can clearly see that
`Ø ∈ = (-pi/2 , pi/2)`
So, we cannot have a phase difference of 180° or 120°.
APPEARS IN
संबंधित प्रश्न
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.
In a series LR circuit, XL = R and power factor of the circuit is P1. When capacitor with capacitance C such that XL = XC is put in series, the power factor becomes P2. Calculate P1/P2
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.
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.
Transformers are used ______.
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
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
Consider the situation of the previous problem. Find the average electric field energy stored in the capacitor and the average magnetic field energy stored in the coil.
Following figure shows a typical circuit for a low-pass filter. An AC input Vi = 10 mV is applied at the left end and the output V0 is received at the right end. Find the output voltage for ν = 10 k Hz, 1.0 MHz and 10.0 MHz. Note that as the frequency is increased the output decreases and, hence, the name low-pass filter.
The power factor in a circuit connected to an A.C. The value of power factor is ______.
Quality factor and power factor both have the dimensions of ______.
The power factor of series LCR circuit when at resistance is
Which of the following quantities remains constant in a step-down Transformer?
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:
A 100 Ω electric iron is connected to 200 V, 50 Hz ac source. Calculate average power delivered to iron, peak power and energy spent in one minute?
In the series LCR circuit, the power dissipation is through ______
The coefficient of induction of a choke coil is 0.1 H and resistance is 12 Ω. If it is connected to an a.c source of frequency 60Hz. Then the power factor will be ______.
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 ______.
An inductor of reactance 1 Ω and a resistor of 2 Ω are connected in series to the terminals of a 6 V (rms) a.c. source. The power dissipated in the circuit is ______.
