* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download unit * 2 objective type questions
Survey
Document related concepts
Opto-isolator wikipedia , lookup
Regenerative circuit wikipedia , lookup
Radio transmitter design wikipedia , lookup
Standby power wikipedia , lookup
Valve RF amplifier wikipedia , lookup
Surge protector wikipedia , lookup
Index of electronics articles wikipedia , lookup
Audio power wikipedia , lookup
Power electronics wikipedia , lookup
Wireless power transfer wikipedia , lookup
RLC circuit wikipedia , lookup
Power MOSFET wikipedia , lookup
Captain Power and the Soldiers of the Future wikipedia , lookup
Transcript
UNIT – 2 OBJECTIVE TYPE QUESTIONS • 1)The unit of active power is (a) Watt (b) VAR (c) Volt ampere (d) None of these ANS: (a)watt • 2)Power factor in RLC series circuit will be lagging if (a) Inductive drop < capacitive drop (b) Inductive drop > capacitive drop (c) Inductive drop = capacitive drop (d) None of these ANS: (b) • 3)To draw the phasor diagram of a reactive circuit having a number of branches connected in parallel across a common voltage source , which of the following is more convenient to use as the reference phasor (a) Circuit current (b) Branch current (c) Source voltage (d) None of these ANS: (c) • 4)When a number of impedances are connected in parallel , the most convenient form to analyse a network is to express (a) Impedances in cartesian form (b) Admittances in cartesian form (c) Admittances in polar form (d) None of these ANS: (c) • 5)When a resistance is connected across an a.c. Voltage source, the frequency of the power wave is? (a) Equal to frequency of voltage wave (b) Equal to frequency of current wave (c) Twice that of voltage and current waves (d) None of these ANS: (c) • 6)The average of a power waveform is given by (a) (Vm Im)/2 (b) VI (c) I(RI) (d) All of these ANS: (d) • 7) The power consumed in a pure inductive circuit is (a) Zero (b) (Vm Im)/2 (c) VI (d) I(LI) ANS: (a) • 8)Which of the following apply to the power curve of a pure capacitance when it is connected across a voltage source? (a) Positive power means that the capacitance is absorbing power (b) Negative power means that the capacitance is returning power to the source (c) There is a continuous exchange of power between the capacitance and the source (d) All of these ANS: (d) • 9)Power in a reactive circuit having resistance is constituted of two components . The two components of power are called (a) real power (b) Reactive power (c) Quadrature power (d) All of these ANS: (d) • 10)Reactive power in a circuit signifies (a) Energy consumed by the magnetic/electric field (b) Energy consumed by the resistance of the inductance/capacitance (c) Energy exchanged between magnetic/electric field and the source (d) Energy consumed by the resistance in the circuit ANS: (c) • 11) Which of the following apply to power in a purely reactive power (a) P=0 and Q=0 (b) P is max and Q=0 (c) P=0 and Q is max (d) P and Q are max ANS: (c) • 12)The product of voltage and current is called (a) True power (b) Reactive power (c) Apparent power (d) None of these ANS: (c) • 13)Complex power in a.c. Circuit is represented by (a) VI (b) V* I* (c) V* I (d) V I* ANS: (d) • 14)Unit of apparent power in an a.c. Circuit is (a) Watt (b) Volt-ampere (c) Volt-ampere reactive (d) All of these ANS: (b) • 15)The power factor of a circuit can be obtained by (a) (volt-ampere reactive)/(apparent power) (b) (real power)/(apparent power) (c) (volt-ampere reactive)/(real power) (d) (real power)/(volt-ampere reactive) ANS: (b) • 16)Heat losses in any electrical device , such as a generator , motor , etc., are independent of (a) Voltage (b) Current (c) Power factor (d) All of these ANS: (c) • 17) From the point of view of electrical utilities , which of the following are of economic importance? (a) Power (b) Reactive power (c) Apparent power (d) All of these ANS: (d) • 18)Which of the following forms of tariff will encourage the consumers to have power factor? (a) High charge for kVA and low charge for kW (b) Low charge for kVA and low charge for kW (c) Low charge for kVA and high charge for kW (d) High charge for kVA and high charge for kW ANS: (a) • 19)In a series RLC circuit , resonance occurs when (a) L=C (b) R=C (c) R=L (d) XL=XC ANS: (d) • 20)When an RLC circuit is in resonance , the current through the circuit is determined by (a) V/XL (b) V/R (c) V/XC (d) None of these ANS: (b) • 21)When a pure LC parallel circuit is in resonance the circuit condition can be represented by (a) A short circuit (b) An open circuit (c) A normal parallel circuit (d) None of these ANS: (b) • 22)In a parallel RLC circuit , under the condition of resonance which of the following are applicable (a) The conductance is maximum (b) The current is maximum (c) The current is in phase with the voltage (d) None is these ANS: (c) • 23)Which of the following conditions is common to both series and parallel resonance? (a) Impedance is minimum (b) Power factor is unity (c) Power is low (d) None of these ANS: (b) • 24)Which of the following theorems can be modified to analyse a.c. Networks (a) Superposition (b) Thevinin (c) Maximum power transfer (d) All of these ANS: (d) • 25)When a series circuit is in resonance , it allows a large magnitude of current to flow on either side of the resonant frequency In such a condition , the circuit behaviour is termed as (a) Rejector (b) Acceptor (c) Neutral (d) None of these ANS: (b) • PREPARED BY K.SUHAS REDDY CSE-D