What is the reactive power in an ac circuit?

What is the reactive power in an ac circuit?
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1 Answer

Answer :

Reactive power is the power returned to the source by the  reactive components of the circuit.
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Related questions

Which of the following statements concerning AC circuits is correct? A. The power factor of a resistive circuit is always zero. B. True power in an inductive circuit always equals apparent power. C. Inductive reactance varies directly with the frequency and the inductance. D. Total opposition to the flow of alternating current depends upon the amount of reactive power.

Description : Which of the following statements concerning AC circuits is correct? A. The power factor of a resistive circuit is always zero. B. True power in an inductive circuit always equals apparent power. ... . D. Total opposition to the flow of alternating current depends upon the amount of reactive power.

Last Answer : Answer: C

What is the true power in an ac circuit?

Description : What is the true power in an ac circuit?

Last Answer : True power is the power dissipated in the resistance of the circuit or the power actually used in the circuit.

What is the formula for calculating reactive power?

Description : What is the formula for calculating reactive power?

Last Answer : Reactive Power = (IX)2X

What is the unit of measurement of reactive power?

Description : What is the unit of measurement of reactive power?

Last Answer : var.

The energy consumed by an AC motor, as strictly reactive power, is _____________. A. used to do mechanical work B. used to establish the magnetic field of the motor C. lost as heat generated by the windings D. lost in doing work to turn the motor itself

Description : The energy consumed by an AC motor, as strictly reactive power, is _____________. A. used to do mechanical work B. used to establish the magnetic field of the motor C. lost as heat generated by the windings D. lost in doing work to turn the motor itself

Last Answer : Answer: B

The reactive power drawn by a motor from an AC generator is the power which is _____________. A. used to establish the magnetic field of the motor B. lost in overcoming friction in the bearings C. strictly converted to heat generated by current flow through the windings D. transmitted directly through the rotor shaft to perform useful work

Description : The reactive power drawn by a motor from an AC generator is the power which is _____________. A. used to establish the magnetic field of the motor B. lost in overcoming friction in the ... by current flow through the windings D. transmitted directly through the rotor shaft to perform useful work

Last Answer : Answer: A

Explain the terms real power, apparent power and reactive power for ac circuits and also the units used.

Description : Explain the terms real power, apparent power and reactive power for ac circuits and also the units used.

Last Answer : Real Power: It is the product of voltage, current and power factor i.e. P = V I cos j and basic unit of real power is watt. i.e. Expressed as W or kW. Apparent power: It is the product of ... X current X sinj or Reactive power = V I sin j and has no other unit but expressed in VAR or KVAR.

What is the difference between calculating impedance in a series ac circuit and in a parallel ac circuit?

Description : What is the difference between calculating impedance in a series ac circuit and in a parallel ac circuit?

Last Answer : In a series circuit impedance is calculated from the values of resistance and reactance. In a parallel circuit, the values of resistive current and reactive current must be used to calculate total impedance.

What is the value of Z in a series ac circuit where XL = 6ohms, XC = 3ohms, and R = 4ohms?

Description : What is the value of Z in a series ac circuit where XL = 6ohms, XC = 3ohms, and R = 4ohms?

Last Answer : X = XL – XC or X = XC - XL

What term is given to total opposition to ac in a circuit?

Description : What term is given to total opposition to ac in a circuit?

Last Answer : Impedance

The division of the reactive KVA load between paralleled AC generators is initiated by the ______________. A. prime mover governors B. voltage regulators C. phase balance relay D. proportioner

Description : The division of the reactive KVA load between paralleled AC generators is initiated by the ______________. A. prime mover governors B. voltage regulators C. phase balance relay D. proportioner

Last Answer : Answer: B

Which is a function of the voltage regulators used with AC generators? A. To cut out generators when they are no longer required. B. To cut in additional generators automatically as required. C. To divide the KW load equally between generators operating in parallel. D. To divide reactive current between generators operating in parallel.

Description : Which is a function of the voltage regulators used with AC generators? A. To cut out generators when they are no longer required. B. To cut in additional generators automatically as ... between generators operating in parallel. D. To divide reactive current between generators operating in parallel.

Last Answer : Answer: D

The apparent power in a purely inductive circuit is also known as _____________. A. true power B. lead power C. induced power D. reactive power

Description : The apparent power in a purely inductive circuit is also known as _____________. A. true power B. lead power C. induced power D. reactive power

Last Answer : Answer: D

Illustrate how can you use a single-phase wattmeter to measure 3 phase reactive power in a circuit?

Description : Illustrate how can you use a single-phase wattmeter to measure 3 phase reactive power in a circuit?

Last Answer : We can measure reactive power of 3 phase circuit by dingle phase wattmeter by connecting the current coil in series with a line or load and connecting the pressure coil across the other two lines.  Reactive power = 3√ V * I * sinϕ Watts. 

Use Voltmeter, ammeter, wattmeter to determine active, reactive and apparent power consumed in given R—C series circuit, draw phasor diagram.

Description : Use Voltmeter, ammeter, wattmeter to determine active, reactive and apparent power consumed in given R—C series circuit, draw phasor diagram.

Last Answer : Use Voltmeter, ammeter, wattmeter to determine active, reactive and apparent power consumed in given R-C series circuit, draw phasor diagram. Practical Significance In the industry environment ... autotransformer position to zero and switch OFF the supply. 8. Draw the phasor diagram.

Use Voltmeter, ammeter, wattmeter to determine active, reactive and apparent power consumed in given R-L series circuit, draw phasor diagram.

Description : Use Voltmeter, ammeter, wattmeter to determine active, reactive and apparent power consumed in given R-L series circuit, draw phasor diagram.

Last Answer : Practical Significance In the industry environment Electrical Engineering diploma graduate are expected to measure basic parameters like voltage, frequency, time period etc. for R-L series circuits. Therefore ... /varying L. 7. Draw the phasor diagram for each of reading for verification.

Draw the circuit diagram for:- i) Measurement of active power in 3-phase load circuit using two wattmeter. ii) Measurement of reactive power in 3-phase load circuit using one wattmeter.

Description : Draw the circuit diagram for:- i) Measurement of active power in 3-phase load circuit using two wattmeter. ii) Measurement of reactive power in 3-phase load circuit using one wattmeter.

Last Answer : (i) Measurement of active power in 3- phase load circuit using two- wattmeter: (ii) Measurement of reactive power in 3- phase load circuit using one wattmeter

Define active power and reactive power for RLC series circuit.

Description : Define active power and reactive power for RLC series circuit.

Last Answer : Active Power (P): Active power (P) is given by the product of voltage, current and the cosine of the phase angle between voltage and current.  Unit: watt (W) or kilo-watt (kW) or Mega-watt ... volt-ampere-reactive (VAr), or kilo-volt-ampere-reactive (kVAr) or Mega-voltampere-reactive (MVAr) 

List any two methods of reactive power measurement in 3 phase circuit.

Description : List any two methods of reactive power measurement in 3 phase circuit.

Last Answer : Methods of reactive power measurement in 3 phase circuit: (i) Two single phase wattmeter method (ii) One single phase wattmeter method

The apparent power drawn by an A.C. circuit is 10 kVA and active power is 8 kW. The reactive power in the circuit is?

Description : The apparent power drawn by an A.C. circuit is 10 kVA and active power is 8 kW. The reactive power in the circuit is?

Last Answer : The apparent power drawn by an A.C. circuit is 10 kVA and active power is 8 kW. The reactive power in the circuit is 6 kVAR.

What leads in a simple synchro system are connected to the ac power line?

Description : What leads in a simple synchro system are connected to the ac power line?

Last Answer : The rotor leads.

Most shipboard distribution systems use ac power that has what number of phases?

Description : Most shipboard distribution systems use ac power that has what number of phases?

Last Answer : Three.

Ships’ generators produce 450-volt, three-phase, ac power; however, most equipment uses 117-volt, single-phase power What transformers and connections are used to convert 450- volt, threephase power to 117-volt, single-phase power?

Description : Ships’ generators produce 450-volt, three-phase, ac power; however, most equipment uses 117-volt, single-phase power What transformers and connections are used to convert 450- volt, threephase power to 117-volt, single-phase power?

Last Answer : A method of generating oscillations, a method of turning the oscillations on and off (keying), and an antenna to radiate the energy.

The voltage phasor of a circuit is 10 ∠15° V and the current phasor is 2∠–45° A. The active and reactive...

Description : The voltage phasor of a circuit is 10 ∠15° V and the current phasor is 2∠–45° A. The active and reactive powers in the circuit are   (a) 20 2 W and 10 2 VAR (b) 10 W and 10 3 VAR (c) 5 W and 5 3 VAR (d) 10 3 W and – 10 VAR 

Last Answer : Angle between voltage and current ¢=15-(-45)=60° Cos60°=1/2  Active power =vicos¢=10×2×1/2=10watt Reactive power=visin¢=10×2×sin60°=20×√3/2=10√3

If an ac voltmeter is connected between the S2 and S3 windings on a TX, at what two rotor positions should the voltmeter read maximum voltage?

Description : If an ac voltmeter is connected between the S2 and S3 windings on a TX, at what two rotor positions should the voltmeter read maximum voltage?

Last Answer : . 150º and 330º

When used for ac current control, during which alternation of the ac cycle does the TRIAC control current flow?

Description : When used for ac current control, during which alternation of the ac cycle does the TRIAC control current flow?

Last Answer : During both alternations.

What is the basic difference between the primaries of ac and dc rate generators?

Description : What is the basic difference between the primaries of ac and dc rate generators?

Last Answer : The method of primary excitation (ac and permanent magnet).

In the output of an ac error detector, what indicates the (a) direction and (b) amount of control necessary for correspondence?

Description : In the output of an ac error detector, what indicates the (a) direction and (b) amount of control necessary for correspondence?

Last Answer : (a) Phase. (b) Amplitude.

What are the electrons called that give up energy to the ac field in a magnetron?

Description : What are the electrons called that give up energy to the ac field in a magnetron?

Last Answer : Working electrons.

Why does using ac vice dc bias voltage result in a stronger output signal?

Description : Why does using ac vice dc bias voltage result in a stronger output signal?

Last Answer : Because an ac bias voltage of the proper frequency and level places the input signal away from both steps in the magnetism curve. The result is two undistorted output signals that are combined into one strong output.

What are three advantages of adding an ac bias voltage to the input signal instead of adding a fixed dc bias voltage?

Description : What are three advantages of adding an ac bias voltage to the input signal instead of adding a fixed dc bias voltage?

Last Answer : a. Reproduces a stronger output signal. b. Greatly improves the SNR. c. Greatly reduces the natural tape hiss.

Why does adding dc vice ac bias voltage to the input signal result in a poor signal-to-noise ratio (SNR)?

Description : Why does adding dc vice ac bias voltage to the input signal result in a poor signal-to-noise ratio (SNR)?

Last Answer : With dc bias, the SNR is poor because only a small portion of the magnetism curve is straight enough to use, thus the output signal is weak compared with the natural tape hiss.

rid-leak biasing in effect rectifies the input ac signal. What feature

Description : rid-leak biasing in effect rectifies the input ac signal. What feature

Last Answer : Unequal charge and discharge paths of the coupling capacitor Cc.

If the mu of a tube is 85 and the signal at the control grid is 4 volts ac, the plate voltage will vary by what amount?

Description : If the mu of a tube is 85 and the signal at the control grid is 4 volts ac, the plate voltage will vary by what amount?

Last Answer : 340 volts.

The plate voltage of a tube will vary 126 volts when a 3-volt ac signal is applied to the control grid. What is the gain of this tube?

Description : The plate voltage of a tube will vary 126 volts when a 3-volt ac signal is applied to the control grid. What is the gain of this tube?

Last Answer : 42.

An ac voltage is applied across a diode. The tube will conduct when

Description : An ac voltage is applied across a diode. The tube will conduct when

Last Answer : Positive.

What is the term for the opposition that a capacitor presents to ac?

Description : What is the term for the opposition that a capacitor presents to ac?

Last Answer : Capacitive reactance.

What is the term for the opposition an inductor presents to ac?

Description : What is the term for the opposition an inductor presents to ac?

Last Answer : Inductive reactance.

What component causes a generator to produce dc voltage rather than ac voltage at its output terminals?

Description : What component causes a generator to produce dc voltage rather than ac voltage at its output terminals?

Last Answer : A commutator

Why should you avoid using ac-powered test equipment when wearing a wrist strap?

Description : Why should you avoid using ac-powered test equipment when wearing a wrist strap?

Last Answer : For your own safety.

Why is the dc scale on a multimeter different than the ac scale?

Description : Why is the dc scale on a multimeter different than the ac scale?

Last Answer : The meter movement reacts to average ac voltage and current and the effective value is desired.

List three meter movements that can measure either ac or dc without the use of a rectifier.

Description : List three meter movements that can measure either ac or dc without the use of a rectifier.

Last Answer : Electrodynamic, moving vane, and hot-wire or thermocouple.

What value is indicated on the scale of an ac meter?

Description : What value is indicated on the scale of an ac meter?

Last Answer : Effective value (rms).

What value does a meter movement react to (actually measure) when measuring ac?

Description : What value does a meter movement react to (actually measure) when measuring ac?

Last Answer : Average value.

How can a d’Arsonval meter movement be adapted for use as an ac meter?

Description : How can a d’Arsonval meter movement be adapted for use as an ac meter?

Last Answer : By the use of a rectifier

The frequency response of test equipment refers to what aspect of ac voltage measurements?

Description : The frequency response of test equipment refers to what aspect of ac voltage measurements?

Last Answer : the range of frequencies that can accurately be measured.

What determines the phase relationship between the voltages in a two-phase ac generator?

Description : What determines the phase relationship between the voltages in a two-phase ac generator?

Last Answer : Placement of armature coils.

What type of ac motor is most widely used?

Description : What type of ac motor is most widely used?

Last Answer : Single-phase induction motor.

Why is the ac induction motor used more often than other types?

Description : Why is the ac induction motor used more often than other types?

Last Answer : They are simple and inexpensive to make.

What are the three basic types of ac motors?

Description : What are the three basic types of ac motors?

Last Answer : Series, synchronous, induction.