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Q.1 For the given circuit the value of R such that the
same amount of power is supplied to the 100Ω
by the current and voltage source will be R = --------100Ω
10A
R
20Ω
100V
ANSWER1. R = 10Ω
Q.2 For the given circuit the thevenin’s voltage and
thevenin’s resistance between A and B will be
(i) 20/3V, 16Ω
(ii) 16V, 20/3 Ω
(iii) 20/3 V, 14Ω
(iv) None of these
ANSWER2. (II) 16V, 20/3 Ω
Q. 3 THREE RESISTORS R, 2R, 3R ARE CONNECTED
IN DELTA THE RESISTANCE FOR A EQUIVALENT STAR
CONNECTION WILL BE
(I) R/3, R, R/2
(II) R, R2, R/3
(III) 2R3, R/4, R
(IV) NONE OF THESE
ANSWER3. (i) R/3, R, R/2
•Q.4 THE CURRENT FLOW THROUGH THE 15Ω
RESISTANCE WILL BE
(I) 5A
(III) 3A
(II) 10A
(IV) ZERO
ANSWER4. (iv) zero
Q.5 THE VALUE OF R TO HAVE MAX. POWER
TRANSFER IN THE CIRCUIT SHOWN IN FIG. WILL
BE
(i) 63/18 Ω (ii) 63/28 (iii) 63/65 (iv) None of these
ANSWER5. (iv) None of these
Q. 6. ACCORDING TO KIRCHOFF’S LAW THE ALGEBRAIC
SUM OF VOLTAGE DROPS IN SERIES CIRCUIT IS EQUAL TO
(I) THE CURRENT IN THE CIRCUIT
(II) THE APPLIED EMF
(III) SUM OF ALL POTENTIAL DROPS IN THE CKT.
(IV) SUM OF THE EMF TAKEN IN THE ORDER
ANSWER6 (II) THE APPLIED EMF
Q. 7. THE NORTON’S EQUIVALENT CIRCUIT OF THE
GIVEN NETWORK BETWEEN A AND B IS CURRENT
SOURCE WITH PARALLEL RESISTANCE OF
(I) 2A, 6Ω
(II) 3A, 2Ω (III) 2A, 3Ω (IV) 3A, 9Ω
ANSWER7. (II) 3A, 2Ω
Q. 8. IN THE GIVEN CIRCUIT WHEN AB TERMINALS ARE
SHORT CIRCUITED. THE CURRENT FLOW THROUGH 4Ω
RESISTANCE IS EQUAL TO
(i) 4Amp
(ii) zero
(iii) 2Amp
(iv) 1Amp
ANSWER8. (ii) zero
Q. 9 ACTIVE ELEMENTS WILL BE
(I) VOLTAGE SOURCE
(II) CURRENT SOURCE
(III) RESISTANCE
(IV) BOTH (I) & (II)
ANSWER-
9. (iv) BOTH (i) & (ii)
Q. 10. A 12V SOURCE WITH AN INTERNAL RESISTANCE
OF 1.2Ω IS CONNECTED ACROSS A LOAD. MAX. POWER
DISSIPATED BY THE LOAD WHEN ITS RESISTANCE IS
EQUAL TO
(I) ZERO
(III) 12Ω
(II) 1.2Ω
(IV) INFINITY
ANSWER10. (ii) 1.2Ω
Q.11 The instantaneous voltage and current for an ac
circuit are
V = 180.8 sin388t Volt, I = 8.95 sin(388t – 36.87)A.
The phaser diagram will be
ANSWER11. (i)
Q.12 A series RLC circuit has the following parameter,
R = 10Ω, L = 0.01H, C = 100µF. The quality factor of
the circuit at resonance is
(i) 1
(ii)2
(iii)3
(iv)4
ANSWER12. (i) 1
Q.13 If resonant frequency of the circuit in fig. 1 is
1KHz. The resonant frequency of the circuit shown
in fig. 2 will be
(i) 4KHz
(ii) 2KHz
(iii) 0.5KHz
(iv) 0.25Hz
ANSWER13. (iii) 0.5KHz
Q.14 If power factor of circuit is unity its reactive
power is
(i) zero
(iii) equal to I2R
(ii) maximum
(iv) a negative quantities
ANSWER14. (i) zero
Q.15 In series R-C circuit as frequency increases
(i) current decreases
(ii) current remain same
(iii) current increase
(iv) None of these
ANSWER15. (iii) current increase
Q.16 A single phase 50Hz motor takes 20A at
0.75pf lagging from a 230V sinusoidal supply. If a
capacitor is connected in parallel to raise the power
factor to 0.9 lagging. The new supply current is
(i) 16.67A
(iii) 14.67A
(ii) 15.67A
(iv) 15A
ANSWER16. (i) 16.67A
Q.17 The voltage and current through circuit
elements are V = 100 sin(314t + 45),
I = 10 sin(314t +315)A. The circuit elements will be
(i) L
(iii) C
(ii) R
(iv) None of these
ANSWER17. (i) L
Q.18 An iron choke coil takes 4A when connected to
a 20V dc supply and takes 5A from 65V, 50Hz ac
supply. The inductive reactance of coil will be
(i) 14Ω
(iii) 18Ω
(ii) 16Ω
(iv) 12Ω
ANSWER18. (iv) 12Ω
Q.19 A resistor of 25Ω is connected in parallel with
capacitor where capacitive resistance is 40Ω. The
parallel circuit is connected across 100V, 50Hz
supply. The total current drown from the supply is
(i) 6.5A
(iii) (4 – j2.5)A
(ii) (4 + j2.5)A
(iv) (2.5 + j4)A
ANSWER19. (ii) (4 + j2.5)A
Q.20 In star connected 3ф system , the angle
between the line current and the corresponding line
voltage is equal to
(i) 30 + ф
(iii) 90 + ф
(ii) 120 + ф
(iv) None of these
ANSWER20. (i) 30 + ф
Q.21 Three 100Ω resistors are connected in delta
across 400V, 3 phase supply, if one of the resistor
disconnected then the phase current will
(i) 4/√3 A
(iii) 4 Amp
(ii) 4√3 A
(iv) None of these
ANSWER21. (iii) 4 Amp
Q.22 Three similar coils each having a resistance
of 8 and inductance of 0.0191H in series in each
phase is connected across 400V, 3ф 50Hz supply
( Assume system is connected in star). The input
power will be
(i) 14.8Kw
(iii) 10Kw
(ii) 12.8Kw
(iv) 16Kw
ANSWER22. (ii) 12.8Kw
Q. 23 In a balanced 3ф delta connected system the
relation between phase current and line current (I L)
is
(i) Iph = √3 IL
(iii) Iph = IL/√2
(ii) Iph = IL/2
(iv) Iph = 0.577 IL
ANSWER23. (iv) Iph = 0.577 IL
Q.24 In a 3ф power measurement by two wattmeter
method, the reading of one of the wattmeters was
-ve. The power factor of the load must be
(i) Greater then 0.5
(iii) equal to 0.5
(ii) less then 0.5
iv) -ve
ANSWER24. (ii) less then 0.5
Q.25 Two wattmeter method is used to measure
the power taken by a 3ф induction motor on No
load. The wattmeter readings are 375W and -50W.
The power factor of motor at no load will be
(i) 0.404 lag
(iii) unity pf
(ii) 0.5 lag
(iv) 0.85 lag
ANSWER25. (i) 0.404 lag
Q.26 Energy meter is
(i) An indicating Instrument (ii) Integrating Inst.
(iii) recording Inst.
(iv) Absolute Inst.
ANSWER26. (ii) Integrating Inst.
Q.27 The value of resistance required to extend the
range of voltmeter is given by the relation
(i) R = Rm/m-1
(iii) R = (m-1)Rm
(ii) R = Rm/m+1
(iv) R = (m+1)Rm
ANSWER27. (iii) R = (m-1)Rm
Q.28 In three phase circuit for zero power factor,
the power measured by two watt meter is
(i) 2 watt
(iii) 4 watt
(ii) zero
(iv) 6 watt
ANSWER28. (ii) zero
Q. 29 The Norton’s equivalent of circuit consists of
2A current source in parallel with 4Ω resistance the
thevenin’s equivalent voltage and thevenin’s
resistance will be equal to
(i) 8V, 4Ω
(iii) 0.5V, 4Ω
(ii) 2V, 6Ω
(iv) 2V, 0Ω
ANSWER29. (i) 8V, 4Ω
Q.30 For the given circuit the mesh equation will be
(i) V1 + V2 + V3 + V4 = I1R1 + I1R2 – I1R3 – I1R4 – I1R5
(ii) - V1 - V2 + V3 + V4 = I1(R1+R2+R3+R4+R5)
(iii) V1 + V2 - V3 + V4 = I1(R1+R2+R3+R4+R5)
(iv) None of these
ANSWER30. (ii)
- V1 - V2 + V3 + V4 = I1(R1+R2+R3+R4+R5)
Q .31 If frequency of power supply in pure inductive
circuit is doubled. The current will be
(i) doubled
(iii) remains same
(ii) half
(iv) None of these
ANSWER31. (ii) half
Q.32 The admittance of circuit is represented by
(8 + j10) which implies that the circuit is
(i) Inductive
(iii) purely capacitive
(ii) Capacitive
(iv) none of these
ANSWER32. (ii) Capacitive
Q.33 The dynamic impedance of R-L-C parallel
circuit at resonance in given by
(i) C/LC
(iii) R/LC
(ii) LC/R
(iv) L/CR
ANSWER33. (ii) LC/R
Q.34 The order in which voltage in 3 phase reach
their maximum +ve value is called
(i) phase sequence
(iii) peak value
(ii) phase angle
(iv) None of these
ANSWER34. (i) phase sequence
Q.35 The force responsible for reduction of
oscillation of pointer in an ammeter is
(i) compelling force
(iii) deflecting force
(ii) damping force
(iv) None of these
ANSWER35. (ii) damping force