Download unit * 2 objective type questions

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