This document contains a summary of basic electrical engineering concepts and multiple choice questions related to resistivity, circuits, current, charge, Ohm's law, and Kirchhoff's laws. Some key points covered include: - Resistivity depends on material and cross-sectional area of a wire. - Ampere-seconds can be a unit of charge. - Parallel circuits have the same potential difference across components but different currents. - Mesh analysis uses Kirchhoff's current law and is applied to networks with lumped parameters. - Nodal analysis uses Kirchhoff's current law and is based on nodes and branches in a circuit.

1. Basic Electrical Engineering
UNIT I
1.Resistivity of a wire depends on
(A) length(B) material (C) cross section area (D) none of the above.
2. The charge on an electron is known to be 1.6 x 10-19
coulomb. In a circuit the current flowing
is 1 A. How many electrons will be flowing through the circuit in a second?
(A) 1.6 x 1019
(B) 1.6 x 10-19
(C) 0.625 x 1019
(D) 0.625 x 101
3. Ampere second could be the unit of
(A) power (B) conductance (C) energy (D) charge
4. A circuit contains two un-equal resistances in parallel
(A) current is same in both (B) large current flows in larger resistor
(C) potential difference across each is same(D) smaller resistance has smaller conductance.
Five resistances are connected as shown and the combination is connected to a 40 V supply.
5. Voltage between point P and Q will be
(A) 40 V (B) 22.5 V (C) 20 V (D) 17.5 V.
6.The current in 4 ohm resistor will be
(A) 2.1 A (B) 2.7 A (C) 3.0 A (D) 3.5 A.
7.Least current will flow through
(A) 25 ohm resistor(B) 18 ohm resistor (C) 10 ohm resistor (D) 5 ohm resistor
8. The sum of all the potential changes in a closed circuit is zero, the stated law is called

2. (A)Kirchhoff's first rule (B)Kirchhoff's voltage rule
(C)Kirchhoff's third rule (D)Kirchhoff's fourth rule
9. Objects that allow electrical current to flow are called ______.
A)Battery B) Nonconductors C)Conductors D)Circuit
10.The current is measured by
A)Ohm meterB)Electro meterC)VoltmeterD)Ammeter
11.In Series Circuit, which of the following quantity remains same through out the circuit
A)VoltageB)CurrentC)Current and VoltageD)None of the above
12. KCL is applied for
A) nodal analysisB) mesh analysis C) loop analysis D) None
13. Which formula is correct for a circuit with two resistors R1 and R2 are connected in parallel?
A)It=I1+I2 B) Rt=R1+R2 C)Vt=V1+V2 D)Vt=1/V1+1/V2
14.What is the total resistance in of 45ohm and 36ohm resister in parallel?
A)9ohm B)20ohm C)40.5ohm D)81ohm
15.Two resistances of 5ohm and 20ohm are connected in parallel. The parallel combination is
connected in series with a 1ohm resistance and this series parallel combination is connected
across a dc source of 100V. The current supplied by the source
A) 20A B) 28A C)30A D)40A
16. What is the power loss of a 100ohm resistor that developes 5V across it ?
A) 50mW B)250mW C)500mW D)5mW
17. Determine the Leq of a parallel combination of 100 mH, 50mH and 10mH…..
A) 0.13mH B) 8mH C) 6.9Mh D) 0.72mH
18.If a resistor has 5.5 V across it and 3mA flowing through it, what is the power
A) 19mW B) 16.5mW C) 18.5mW D) 15.5 Mw

3. 19.If R1 and R2 are in series to the voltage of V volts, then drop across R2 is
A) V. R2/(R1+R2) B) V. R2/(R1-R2) C) V/(R1+R2) D) V. R2/(R1+R2)
20.. Kirchhoff’s Voltage Law is based on Law of Conservation of
(A) Energy(B) charge (C) Voltage (D) None
21. When n resistances each of value r are connected in parallel, then resultant resistance is x.
When these n resistances are connected in series, total resistance is
(A) nx (B) rnx (C) x / n (D) n2
x.
22. Resistance of a wire is r ohms. The wire is stretched to double its length, then its resistance in
ohms is
(A) r / 2 (B) 4 r (C) 2 r (D) r / 4.
23. Kirchhoff's second law is based on law of conservation of
(A) charge (B) energy (C) momentum (D) mass.
24. The charge on an electron is known to be 1.6 x 10-19
coulomb. In a circuit the current flowing
is 1 A. How many electrons will be flowing through the circuit in a second?
(A) 1.6 x 1019
(B) 1.6 x 10-19
(C) 0.625 x 1019
(D) 0.625 x 1012
.
25. Two bulbs marked 200 watt-250 volts and 100 watt-250 volts are joined in series to 250 volts
supply. Power consumed in circuit is
(A) 33 watt (B) 67 watt (C) 100 watt (D) 300 watt.
26. Ampere second could be the unit of
(A) power (B) conductance (C) energy (D) charge.
27. Which of the following is not the same as watt?
(A) joule/sec (B) amperes/volt (C) amperes x volts (D) ( amperes )2
x ohm.
28. One kilowatt hour of electrical energy is the same as
(A) 36 x 105
watts (B) 36 x 10s
ergs (C) 36 x 105
joules (D) 36 x 105
B.T.U.

4. 29. The value of the following is given by 100 (kilo ampere ) x ( micro ampere ) 100 milli
ampere * 10 ampere
(A) 0.001 A (B) 0.1 A (C) 1 A (D) 10A.
30. A circuit contains two un-equal resistances in parallel
(A) current is same in both (B) large current flows in larger resistor
(C) potential difference across each is same (D) smaller resistance has smaller conductance.
31.A wire of 0.14 mm diameter and specific resistance 9.6 micro ohm-cm is 440 cm long. The
resistance of the wire will be
(A) 9.6 ohm (B) 11.3 ohm (C) 13.7 ohm (D) 27.4 ohm.
32.A resistance of 5 ohms is further drawn so that its length becomes double. Its resistance will
now be
(A) 5 ohms (B) 7.5 ohms (C) 10 ohms (D) 20 ohms.
33.Specific resistance of a substance is measured in
(A) ohms (B) mhos (C) ohm-cm (D) cm/ohm.
34. 40 W bulb A will be least bright when
(A) only keys k1 and k2 are open
(B) only keys k2 is open
(C) only keys k3 is open
(D) all keys are closed.

5. 35. The power consumption of the circuit will be maximum when
(A) key k1 and k3 are closed and k2 is open
(B) key k1 is closed, k2 and k3 are open
(C) key k1 and k2 are closed and k3 is open
(D) all the keys are closed.
36. Which of the following lamps will have least resistance at room temperature ?
(A) 200 W, 220 V
(B) 100 W, 220 V
(C) 60 W, 220 V
(D) 25 W, 220 V.
37. Filaments of electric bulbs are usually made of
(A) Nichrome
(B) Tungsten
(C) Copper
(D) Carbon.
38. The value of supply voltage for 500 W ,5 ohm load is
(A) 500 V
(B) 100V
(C) 50 V
(D) 10V.

6. 39. 100 resistors of 100 ohms each arc connected in parallel. Their equivalent resistances will be
(A) 10,000 ohms
(B) 100 ohms
(C) 1 ohm
(D) 1/ 10000 ohm.
40. Two loads X and Y, are connected in parallel to a 115 V supply. Load X takes 35 watts and
the total current is 2.6 A. The resistance of X is
(A) 379 ohms
(B) 291 ohms
(C) 233 ohms
(D) 190 ohms.
41. Kirchhoff's laws are applicable to circuits with
a) Distributed parameters
b) Lumped parameters
c) Passive elements
d) Non-linear resistances
42. An ideal current source has:
a) Zero internal conductance
b) Zero internal resistance
c) Zero voltage on no load
d) Zero ripples
43.An ideal voltage source should have:
a) Zero source resistance
b) Infinite source resistance
c) Terminal voltage is proportional to current
d) Open-circuit voltage nearly equal to voltage of the load current
44. The unit of resistivity is
a) ohms
b) ohm-metre
c) coulomb
d) none

7. 45. The resistance of a wire depends on
a) Length
b) Area of cross section
c) Both A and B
d) None
46. The equivalent capacitance when two capacitors C1 and C2 are connected in parallel is
a) C1/C2 b) C1+C2 c) C1-C2 d) C1*C2
47. Two resistors are said to be connected in series when
a) Current is same
b) Current is not same
c) Voltage is same
d) None
48. The sources which supply energy are termed as
a) Active elements b) passive elements
c) Both A and B d) None
49. If the value of the source changes with respect to other quantity, it is termed as
a) Independent source b) Current source
c) Dependent source d) None
50. If the value of an element changes with respect to current direction, it is termed as
a) Active element b) Passive element
c) Unilateral element d) Bilateral element
KEY
1)B 2)C 3)D 4)C 5)B 6)D 7)A 8)B 9)C 10)D
11)B 12)A 13)A 14)B 15)A 16)B 17)A 18)B 19)D 20)A
21)D 22)B 23)B 24)C 25)B 26)D 27)B 28)C 29)B 30)C
31)D 32)D 33)C 34)A 35)A 36)A 37)B 38)C 39)C 40)A
41)A 42)A 43)A 44)B 45)C 46)B 47)A 48)A 49)C 50)D

8. UNIT-II
1.How many meshes are present within the following circuit?
A) 1 B) 2 C) 3 D) 4
2. What is the equivalent inductance of two inductive coils of 5H and 10H connected in series is
A) 15H B)25H C)35H D)10H
3. Find I2.
4I1 + 4I2 = 2
6I1 + 7I2 = 4
A)1 A B)-1 A C)100mA d)-100mA
4.Mesh analysis is based on
A)Kirchhoff current law B)Kirchhoff voltage law
C)Both D)None
5.If a network contains B Branches, and N nodes, then the number of mesh current equations
would be
A) B-(N-1) B)N-(B-1) C)B-N-1 D)(B+N)-1
6.The nodal method of circuit analysis is based on
A)KVL and Ohms law B)KCL and Ohms law C)KCL and KVL D)KCL , KVL and Ohms law
7. A circuit consists of two resistances, R1 and R2 in parallel. The total current passing through
the circuit is IT .The current passing through R1 is
A)
𝐼𝑇𝑅1
𝑅1+𝑅2
B)
𝐼𝑇(𝑅1+𝑅2)
𝑅1
C)
𝐼𝑇𝑅2
𝑅1+𝑅2
D)
𝐼𝑇(𝑅1+𝑅2)
𝑅2
8.Nodal analysis based on the
A)Source voltage B)Source current C)Both A & B D) None of the above
9.An electrical circuit with 10 branches and 7 nodes will have
A)10 loop equation B)7 loop equation C)3 loop equation D)4 loop equation

9. 10. In given figure, the value of resistance R in Ω is
A)10 B)20 C)30 D)40
11. Link in network theory refers to
A)B-N+1 B)B-N-1 C)N-1 D)N-B-1
12.The linear circuit element is
A)Capacitor B)Inductor C)Resistor D)All of above
13.Active element of electrical circuit is
A)Voltage source B)Current source C)Both of them D)None of above
14. The basic circuit elements are
A)R,L,C B)VS,ISC)Both A &B D)None of above
15. Which of following statements is incorrect?
A) Resistance is a passive element B)Inductor is passive element
C) Capacitor is a passive element D) Voltage source is a passive element.
16. A delta connection contains three equal impedance of 60 Ω. The impedance of the
equivalent star connection for each star load will be
A) 15Ω B)20Ω C)30Ω D)40Ω
17. Delta values are given 2Ω, 3Ω, 2 Ω what will be the star values.
A)0.85Ω, 0.85Ω, 0.57Ω B)0.77 Ω, 0.57Ω, 0.78Ω C)0.88 Ω, 0.54Ω, 0.23Ω
D)None of the above

10. 18.Current Division rule is applied for which of the following
(A) Series Circuits (B) Parallel Circuits (C) both A&B (D) None
19.The star values are like 5Ω what are delta values.
A)15Ω B)12Ω C)13Ω D)5Ω
20.Delta -Star Transformation if equal resistances are given its value is
(A) 3times Increases (B) 3 times reduces (C) same value (D) None
21.Mesh analysis based on
A) Kirchhoff current law B) Kirchhoff voltage law C)Both D)None
22. If a network contain B branches and N nodes then the number of mesh current equations would be
A) B-(N-1) B) N-(B-1) C) B-(N-1) D) (B+N)-1
23. A network has 10 nodes and 17 branches. The number of different node pair voltage would be
A)7 B)9 C)45 D)10
24. A network has 7 nodes and 5 independent loops. The number of branches in the network
A)13 B)12 C)11 D)10
25. The nodal method of circuit analysis is based on
A) KVL and ohms law B) KCL and ohms law C) KCL and KVL D) KCL, KVL and ohms law
26. Three equal resistance of 3Ω are connected in star. What is the resistance in one of the arms in an
equivalent delta circuit
A) 10Ω B) 3Ω C) 9Ω D) 27Ω
27. A 120 V voltage source has a source resistance, RS, of 60ΩThe equivalent current source is
A) 2A B)4A C) 200mA D) 400mA
28) The superposition theorem is applicable to
A) voltage only B) current only C) both current and voltage D) current voltage and power
29) The two basic components of a Thevenin equivalent ac circuit are
A) the equivalent voltage source and the equivalent series resistance
B) the equivalent voltage source and the equivalent parallel impedance
C) the equivalent voltage source and the equivalent parallel resistance
D) the equivalent voltage source and the equivalent series impedance
30) A 120Ω load is connected across an ideal voltage source with Vs=12V.The voltage across the load
A) 0V B) 12V C) 120V D) Cannot be determined

11. 31) Find the Thevenin equivalent (VTH and RTH) between terminals A and B of the circuit given below
A) 4.16 V, 120 B) 41.6 V, 120 C) 4.16 V, 70 D) 41.67 V, 70
32) A 680 load resistor, RL, is connected across a constant current source of 1.2 A. The internal
source resistance, RS, is 12 k . The load current, RL, is
A) 0 A B) 1.2 A C) 114 mA D) 1.14 A
33)Find the current through R2 of the given circuit.
A) 30.7 mA B) 104 mA C) 74 mA D) 134 mA
34)A 120 V voltage source has a source resistance, RS, of 60 . The equivalent current source is
A) 2 A B) 4 A C) 200 mA D) 400 mA
35) A 12 V source has an internal resistance of 90 . If a load resistance of 20 is connected to the
voltage source, the load power, PL, is
A) 2.38 mW B) 2.38 W C) 238 mW D) 23.8 W
36)What is the Thevenin equivalent (VTH and RTH) for the circuit given?

12. A) 6.4 V, 422 B) 6.4 V, 560 C) 6.4 V, 680 D) 30 V, 422
37) Referring to the given circuit, the voltage and current for the load resistor, RL, is
A) 450 mV, 4.5 mA B) 4.50 V, 45 mA C) 4.50 V, 4.5 mA D) 450 mV, 45 mA
38)Find the current in R2 of the given circuit, using the superposition theorem.
A) 16.7 mA B) 33.3 mA C) 50 mA D)16.6 mA
39)A 470 RL is connected across a voltage source, VS, of 120 V. The source's internal resistance, RS,
is 12 . What is the output voltage across the load?
A) 120 V B) 0 V C) 117 V D) 12 V
40) A 2 RL is connected across a voltage source, VS, of 110 V. The source's internal resistance is
24 . What is the output voltage across the load?
A) 8.5 V B) 85 V C) 0 V D) 110 V
41) The condition for maximum power transfer across the load resistance is
a) RL= RS b) RL > RS c) RL < RS d) RL = 2 RS
42) The value of maximum power transferred to the load resistance is
a) Vth/2RL b) Vth2
/2RL c) Vth2
/4RL d) Vth/RL
43) Thevenin’s theorem is useful to calculate
a) Voltage b) current c) Both A& B d) None
44) The basis of maximum power transfer theorem is
a) Superposition theorem b) Thevenin’s theorem c) Norton’s theorem d) All

13. 45) Efficiency of the circuit at the condition of maximum power transfer is
a) 25% b) 45% c) 75% d) 50%
46) In superposition theorem the voltage source is made zero by
a) open circuit b) short circuit c) Both A & B d) None
47) In superposition theorem the current source is made zero by
a) open circuit b) short circuit c) Both A & B d) None
48) The value of load current in Thevenin’s theorem is
a) VTH/( Rth+ RL) b) VTH/( Rth- RL) c) VTH/( Rth+ 2RL) d) VTH/( 2Rth+ RL)
49) Superposition theorem is applicable to
a) Linear network b) Non-Linear network c) Homogeneous network d) Homologous network
50) If the current and voltage increase in proportionate then it is termed as
a) Non- Linear element b) Active elements c) Passive elements d) Linear elements
KEY
1)C 2)A 3)A 4)B 5)A 6)B 7)C 8)B 9)D 10)B
11)A 12)D 13)C 14)C 15)D 16)B 17)A 18)B 19)A 20)A
21)B 22)A 23)C 24)C 25)B 26)C 27) A 28)D 29)D 30)B
31)D 32)D 33) D 34)A 35)C 36)A 37)C 38)C 39)C 40)A
41)A 42)B 43) B 44)B 45)D 46)B 47)A 48)A 49)A 50)D

14. UNIT-III
1) The instrument which is cheapest for dc measurement is:
a) Moving iron
b) PMMC
c) Hot-wire
d) Electro-dynamo
2) Measurement range of a voltmeter can be extended by using:
a) High current resistance
b) High series resistance
c) Low shunt resistance
d) Low series resistance
3) Which of the following voltmeter have least power consumption?
a) Moving iron
b) Hot-wire
c) Electrostatic
d) Induction type
4) Which of the following instruments have least torque/weight ratio:
a) Dynamometer type
b) PMMC
c) Attraction type moving iron
d) Repulsion type moving iron
5) The instrument having its deflection depends upon average value is:
a) Moving iron
b) Hot wire
c) Rectifier type
d) Induction type
6) Which of the following instruments can be used for full scale deflection of 300o
:
a) PMMC
b) Induction type
c) Hot wire
d) Electrostatic
7) While testing cables the galvanometer used should be initially short-circuited in order to protect it from
sudden initial inrush currents as the cable have:
a) A low value of initial resistance
b) A low value of initial capacitance
c) A high value of initial capacitance
d) Both (a) and (b)
8) A Ohmmeter is basically:

15. a) A ammeter
b) A voltmeter
c) A multimeter
d) None of the above
9) Potentiometer is an __ instrument:
a) Indicating
b) Comparison
c) Calibrating
d) Recording
10) Electrostatic type instruments are mainly used for measurement of:
a) Heavy currents
b) Low currents
c) Low voltages
d) High voltages
11) Which of the following instruments indicate the instantaneous value of the electrical quantity being
measured at the time at which it is being measured ?
(a) Absolute instruments (b) Indicating instruments (c) Recording instruments (d) Integrating instruments
12) _____ instruments are those which measure the total quantity of electricity delivered in a particular
time.
(a) Absolute (b) Indicating (c) Recording (d) Integrating
13) Which of the following are integrating instruments ?
(a) Ammeters (b) Voltmeters (c) Wattmeters (d) Ampere-hour and watt-hour meters
14) Resistances can be measured with the help of
(a) wattmeters (b) voltmeters (c) ammeters (d) ohmmeters and resistance bridges
15) Which of the following essential features is possessed by an indicating instrument ?
(a) Deflecting device (b) Controlling device (c) Damping device (d) All of the above
16) A _____ device prevents the oscillation of the moving system and enables the latter to reach its final
position quickly
(a) deflecting (b) controlling (c) damping (d) any of the above
17) A moving-coil permanent-magnet instrument can be used as _____ by using a low resistance shunt.
(a) ammeter (b) voltmeter (c) flux-meter (d) ballistic galvanometer
18) A moving-coil permanent-magnet instrument can be used as flux-meter
(a) by using a low resistance shunt (b) by using a high series resistance (c) by eliminating the control
springs (d) by making control springs of large moment of inertia

16. 19An induction meter can handle current upto
(a) 10 A (b) 30 A (c) 60 A (d) 100 A
20) Induction type single phase energy meters measure electric energy in
(a) kW (b) Wh (c) kWh (d) VAR
21. A transformer works on the principle of
a) Induction b) Self induction
c) Mutual Induction d) None
22. The transformer rating is
a) KW b) KVA
c) KV d) WATT
23. The main purpose of Core in a transformer is to
a) Decrease Iron losses b) Prevent Eddy current losses
c) Eliminate Magnetic hysteresis d) Decrease Reluctance of the Common magnetic
circuit
24. The primary winding in a transformer is
(a) Always a low voltage winding (b) Always a high voltage winding
(c) Could be either low or high voltage winding (d) None
25. The Primary and Secondary induced E.M.Fs E1 & E2 in a two winding transformer are
always
a) Equal in magnitude (b) Anti-Phase with each other
c) In-Phase with each other (d) Determined by load on transformer
Secondary
26. The Step-up transformer increases
a) Voltage b) Current
c) Power d) Frequency
27. The Step-down transformer decreases
a) Voltage b) Current
c) Power d) Frequency
28. The main purpose of performing open circuit test on a transformer is to measure
a) Copper losses b) Iron losses
c) Total losses d) Insulation resistance
29. The main purpose of performing short circuit test on a transformer is to measure its
a) Copper losses b) Iron losses
c) Total losses d) Insulation resistance
30. In a transformer the load is connected to
a) Primary b) Secondary
c) Both (a) & (b) d) None

17. 31. The efficiency of the transformer depends on
a) Input power b) Losses in transformer
c) Power factor d) All the above
32. The transformation ratio is
a) E2/E1 b) N2/N1
c) I1/I2 d) All the above
33. The Cosine angle between the Voltage and Current
a) Power factor b) Voltage
c) Load of the transformer d) Current
34. When the transformer is more efficient
a) Constant load current b) Load power factor is unity
c) Both A&B d) None
35. Which of the following does not change in a transformer?
a) Current b) Voltage
c) Frequency d) All of the above
36. In a transformer Energy is transferred from primary to secondary through
a) Through cooling coil b) through air
c) By the flux d) none of the above
37. The path of magnetic flux in a transformer should have
a) High resistance b) High reluctance
c) Low resistance d) low reluctance
38. The di electric strength of transformer oil is found to be
a) 1 kV b) 33 kV
c) 100 kV d) 330 kV
39. Sumpner’s test on a transformer is conducted to determine
a) Temperature b) Stray losses
c) All day efficiency d) none
40. A transformer transforms
a) Voltage b) Current
c) Power d) None
41. High frequency transformers sometimes make use of ferrite cores because it has
a) High specific gravity b) High resistance
c) High hysteresis d) low permeability
42. Harmonics in transformer result in
a) Increased core losses b) Increased I2R losses
c) Magnetic interference with communication circuits d) All of the above
43. The full load copper loss of a transformer is 1600W. At half-load the copper loss will be
a) 6400W b) 1600W c) 800W d) 400W

18. 44. Power transformers are generally designed to have maximum efficiency around
a) No load b) Half load c) Near full load d)10% overload
45. Two transformers are connected in parallel. These transformers do not have equal percentage
impedance which results
a) Short-circuiting of the secondary’s
b) Power factor of one of the transformers is leading while that of the other lagging
c) Transformers having higher copper losses will have negligible core losses
d) Loading of the transformers not in proportion to their kVA ratings.
46. The changes in volume of transformer cooling oil due to variation of atmospheric
temperature during day and night are taken care of by which part of transformer?
a) Conservator b) Breather c) Bushings d) Buchholz relay
47. The transformer laminations are insulated from each other by
a) Mica strip
b) Thin coat of varnish
c) Paper
d). Any of the above
48. Which type of winding is used in 3 phase shell type transformer?
a) Circular type
b) Sandwich type
c) Cylindrical type
d) Rectangular type
49. During open circuit test of a transformer
a) Primary is supplied rated voltage
b) Primary is supplied full load current
c) Primary is supplied current at reduced voltage
d) Primary is supplied rated kVA
50. Which of the following is not standard voltage for power supply in India
a) 11kV b) 33kV c) 66 kV d) 122 kV
KEY
1)A 2)B 3)C 4)A 5)C 6)B 7)C 8)A 9)B 10)D
11)B 12)D 13)D 14)D 15)D 16)C 17)A 18)C 19)D 20)C
21)C 22) B 23) D 24) C 25) B 26) A 27) A 28) B 29) A 30) B
31) D 32) D 33) A 34) C 35) C 36) C 37) D 38) B 39) A 40) C
41) B 42) D 43) D 44) C 45) D 46) A 47) B 48) B 49) A 50) D

19. UNIT-4
1. Laminations of core are generally made of
(a) Cast iron (b) carbon
(c) Silicon steel (d) stainless steel
2. Which of the following could be approximately the thickness of laminations of a dc machine?
(a) 0.005 mm (b) 0.05 mm
(c) 0.5 m (d) 5 m
3. The armature of D.C. generator is laminated to
(a) Reduce the bulk (b) provide the bulk
(c) Insulate the core (d) reduce eddy current loss
4. The resistance of armature winding depends on
(a) Length of conductor (b) cross-sectional area of the conductor
(c) Number of conductors (d) all of the above
5. The field coils of D.C. generator are usually made of
(a) Mica (b) copper
(c) cast iron (d) carbon
6. The commutator segments are connected to the armature conductors by means of
(a) Copper plugs (b) resistance wires
(c) Insulation pads (d) brazing
7. In a commutator
(a) copper is harder than mica (b) mica and copper are equally hard
(c) Mica is harder than copper (d) none of the above
8. In D.C. generators the pole shoes are fastened to the pole core by
(a) rivets (b) counter sunk screws

20. (c) brazing (d) welding
9. According to Fleming's right-hand rule for finding the direction of induced e.m.f., when
middle finger points in the direction of induced e.m.f., forefinger will point in the direction
of
(a) motion of conductor (b) lines of force
(c) either of the above (d) none of the above
10. Fleming's right-hand rule regarding direction of induced e.m.f., correlates
(a) Magnetic flux, direction of current flow and resultant force
(b) Magnetic flux, direction of motion and the direction of e.m.f. induced
(c) Magnetic field strength, induced voltage and current
(d) Magnetic flux, direction of force and direction of motion of conductor
11. While applying Fleming's right-hand rule to and the direction of induced e.m.f., the
Thumb points towards
(a) Direction of induced e.m.f. (b) Direction of flux
(c) Direction of motion of the conductor if forefinger points in the direction of generated
e.m.f.
(d) Direction of motion of conductor, if forefinger points along the lines of flux
12. The bearings used to support the rotor shafts are generally
(a) ball bearings (b) bush bearings
(c) magnetic bearings (d) needle bearings
13. In D.C. generators, the cause of rapid brush wear may be
(a) severe sparking ` (b) rough commutator surface
(c) imperfect contact (d) any of the above
14. Induced e.m.f in a coil is directly proportional to

21. a) Rate of change of flux linkage b) Rate of change of charge
c) Depends on the material used (d) Rate of change of current
15. Mechanical energy converted to electrical energy in which of the following
a) Generator b) Motor
c) Both A&B D) None
16. The direction of induced e.m.f in a conductor can be determined by
a) Lenz’s Law b) Fleming’s Right hand rule
c) Both A&B d) Fleming’s Left hand rule
17. The function of the commutator segment is
a) ac to dc b) dc to ac
c) Both A&B d) None
18. Brushes in a DC generator are made up of
a) Carbon b) Silicon
c) Copper d) Mild steel
19. Which of the following are Iron Losses?
a) Copper losses b) Mechanical losses
c) Friction loss d) Eddy current losses
20. The Basic Principle of dc generator is
a) Electro Magnetic Induction b) Flemings Left hand rule
c) Law of conservation Energy d) none
21. The Primary and Secondary induced E.M.Fs E1 & E2 in a two winding transformer are
always
a) Equal in magnitude b) Anti-Phase with each other

22. c) In-Phase with each other d) Determined by load on transformer Secondary
22. In a transformer the load is connected to
a) Primary b) secondary c) both a & b d) None
23) The function of the commentator segment is
a) Ac to dc b) dc to ac c) Both A&B d) None
24) An Induction motor is
a) Self-starting with low torque b) Self-starting with zero torque
c) Self-starting with high torque d) Non- Self starting
25) In case of induction motor the torque is
a) Directly proportional to slip b) inversely proportional to slip
c) Directly proportional to square of the slip d) inversely proportional to square of the slip
26) Generator works on the principle of
a) dynamically induced emf b) static induced emf
c) none of the above d) both A & B
27) Armature reaction in dc generators will result in
a) increase in slip b) short circuit c) open circuit d) reduction in generated emf
28) For high current and low current rotating which winding is employed to DC machine
a) wave winding b) lap winding c) both wave and lap winding d) no wave and lap winding
29) secondary current of a step down transformer is
a) lower than primary current b) higher than primary current c) equal to primary current d)
double than primary current
30) The core of transformer must have
a) low reluctance b) high resistance c) high reluctance d) low resistance

23. 31) The working principle of transformer depends upon
a) Ohms law b) Lenz law
c) Fleming left hand rule d) faradays law of electromagnetic
32) In case of a D.C shunt motor under no load condition the air gap flux
a) keeps varying. b) increases. c) remains constant. d) decreases.
33) In DC series motor the speed is ______________ proportional to the armature current.
a) directly. b) inversely. d) has no relation. d) none of these.
34) A compound motor has
a) only shunt field winding. b) only series field winding.
c) both shunt and series field winding. d) tertiary winding.
35) A dc motor with armature resistance of 0.5 ohms connected directly to a 230 Volt supply. If the
armature is stationary then the current flowing through armature is
a) 340 A. b) 250 A. c) 460 A. d) 570 A.
36) A shunt motor of 250 V having armature resistance 0.5 Ohm and no-load current is 2 A. When loaded
and taking a armature current of 20 A. The speed is 1000 r.p.m. The approximate no load speed will be
a) 1037.5 r.p.m. b) 1130 r.p.m. c) 4575.4 r.p.m. d) none of above.
37) The armature of a DC motor is laminated to reduce
a) hysteresis loss. b) eddy current loss. c) copper loss. d) friction and windage loss.
38) A 4 pole lap wound DC shunt motor rotates at the speed of 1500 rpm, has a flux of 0.4 mWb and the
total number of conductors are 1000. What is the value of emf?
a) 10 volts. b) 20 volts c) 30 volts. d) 40 volts.
39) Which of the following motors one will choose to drive paper machine?
a) DC Shunt motor. b) DC compound motor. c) Separately excited motor. d) DC series motor.
40) In electric locomotive which of the following motor are used ?
a) DC series motor. b) Separately compound motor.
c) Synchronous motor. d) Shunt motor.

24. 41. Torque development in a dc motor depends on:
a) Magnetic field and radius of armature
b) Current flowing through the armature conductors
c) Active length of the conductors and number of armature conductors
d) All the above
42. The horse power obtained from the motor shaft is called
a) IHP
b) BHP
c) Useful torque
d) None of the above
43. The efficiency of a dc motor when developing maximum power will be about:
a) 100%
b) 50%
c) Less than 50%
d) More than 50%
44. A dc motor having full load speed of 75 rpm and speed regulation of 10% will have no load
speed of:
a) 825 rpm
b) 675 rpm
c) 800 rom
d) 700 rpm
45. The direction of rotation of a dc compound motor can be reversed by interchanging __
connections:
a) Armature
b) Series field
c) Shunt field
d) Armature and series field
46. A DC shunt motor is running at light load, what happens if the field winding gets opened?
a) Motor will stop
b) Motor will burn
c) Motor will make noise
d) Motor will pick up high speed
47. In an electrical motor, the electromagnetic torque developed is:
a) In opposite direction to both load torque and fractional torque
b) In the same direction to the load torque but opposite direction to the fractional torque
c) In the same direction as the load torque and fractional torque
d) In the same direction as the fractional torque but in opposite direction to the load torque

25. 48. In a dc motor, the shaft torque is less than armature torque . This is due to:
a) Eddy current loss
b) Hysteresis loss
c) Stray loss
d) All the above
49. The starting torque of dc shunt motor is:
a) Zero
b) Low
c) High
d) Very high
50. A DC shunt motor may have rising speed-torque characteristics due to:
a) Very high armature circuit resistance
b) Very high field circuit resistance
c) Very high demagnetizing armature resistance
d) Very low demagnetizing armature reaction
KEY
1) C 2) C 3) D 4) D 5) B 6) A 7) C 8) B 9) B 10) B
11) D 12) A 13) D 14) A 15) A 16) B 17) C 18) A 19) D 20) A
21) B 22) B 23) C 24) B 25) A 26)D 27)D 28)B 29)B 30)A
31)D 32)C 33)B 34)C 35)C 36)A 37)B 38)A 39)B 40)A
41)D 42)C 43)C 44)A 45)A 46)D 47)A 48)C 49)B 50)C

26. UNIT-V
1) Type of single phase motor having highest power factor at full load is
a) Shaded pole type. b) Capacitor runs. c) capacitor start d) split phase
2) Induction motors have the advantage of
a) All of below. b) Less cost c) simple in construction. d) Less maintenance.
3) For a single phase capacitor start induction motor which of the following is valid?
a) Rotation can be changed by reversing main winding terminals.
b) Direction of rotation cannot be changed.
c) Rotation can be changed by interchanging supply terminals.
d) None of these.
4) Which motors are preferred for refrigeration and air conditioning in smaller units?
a) Induction motors. b) Universal motors c) Reluctance motors. d) Stepper motors.
5) Types of rotating machines
a) Both B and C. b) IM c) synchronous machine. d) Transformer.
6) A 230 V, 50 Hz, 4 pole single phase induction motor is rotating in the clockwise (forward)
direction at a speed of 1425 rpm. If the rotor resistance at standstill is 7.8 Ω. Then the effective
rotor resistance in the backward branch of the equivalent circuit will be
a) 2 Ω. b) 4 Ω c) 8 Ω. d) 10 Ω.
7) Which of the following motor used in hair dryers?
a) Synchronous motors. b) Shaded pole IM. c) Split phase IM. d) Cage induction motor.
8) Capacitor start capacitor run provides
a) High staring torque and high power factor.
b) High staring torque only.
c) High power factor only.
d) None.
9) Slip speed is the

27. a) Difference of synchronous speed and actual rotor speed.
b) Difference of actual rotor speed and synchronous speed.
c) Sum of synchronous and rotor speeds.
d) Half of the sum of synchronous and rotor speeds.
10) At slip s = 1 torque developed in machine is
a) Starting torque. b) Maximum torque. c) Electromagnetic torque. d) None.
11) An alternator of 300 kW is driven by a prime mover of speed regulation 4 % and another
alternator of 220 kW driven by a prime mover of speed regulation 3 %. The total load they can
take is
a) 257 kW. b) 425 kW. c) 500 kW. d) 576 kW
12) In a 3 - Φ alternator a field current of 40 A produced a full load current of 200 A on short
circuit and 1732 V on open circuit if the resistance is 1 Ω, the synchronous reactance is
a) 3.4 Ω. b) 8.66 Ω. c) 5.2 Ω. d) 0.6 Ω.
13) An alternator is supplying a load of 300 kW of a power factor of 0.6 lagging. If the power
factor is raised to unity, how many more kilowatts can alternator supply for the same KVA
loading
a) 100 kW. b) 200 kW. c) 300 kW. d) 500 kW
14) The balanced short circuit current of a 3 phase alternator is 50 A at a speed of 1500 rpm for
the same filed current the balanced short circuit current at 1200 rpm would be
a) 24. b) 30 c) 40. d) 62.5.
15) A 3 - Φ 50 Hz, 6000 kVA star connected alternator having an effective resistance of 0.2 Ω. A
field current of 10 A produces 480 V on open circuit and field current of 5 A gives armature
current of 105 A. The full load current and phase voltage will be
a) 577.35 A and 3464 V. b) 980.6 A and 4582 V
c) 234.65 A and 3644 V. d) 376.1 A and 3290 V.
16) To determine the losses of an alternator is driven by
a) Synchronous motor. b) Compensated DC motor. c) Calibrated DC motor. d) AC series motor.

28. 17) The distribution factor for 36 slots, 4 poles, single layer three phase winding alternator will
be.
a) 0.98. b) 0.96. c) 0.35. d) 0.20.
18) Calculate the highest speed at which 50 Hz alternator can operate
a) 6000 rpm. b) 3000 rpm. c) 3000 rps d) none of the above.
19) If two mechanically coupled alternator deliver power at 50 KHz and 60 KHz respectively.
Then highest speed of the alternator is
a) 3600 rpm. b) 4000 rpm. c) 600 rpm. d) 500 rpm.
20) What are the methods for determining regulation of an alternator?
a) Synchronous impedance method. b) MMF method. c) Zero power factor method. d) All of the
above.
21. The speed at which the rotating magnetic field produced by stator currents rotates in an
induction motor is:
a) Synchronous speed b) Rotor speed
c) Greater than synchronous speed d) None
22. A 3-phase 50 Hz induction motor runs at speed of 940 RPM; the speed of the rotating
magnetic field will be:
a) 940 RPM b) 1000RPM
c) 1050 RPM d) 1100 RPM
23. The no-load speed of an induction motor is of the order of
a) 8% b) 4%
c) 2% d) 6%
24. Iron losses in the rotor of a 3-phase induction motor are negligible, because
a) Frequency of rotor emf is too low
b) Flux linking the rotor is of constant magnitude
c) Flux density in the rotor parts is too low
d) None

29. 25. Full-load copper losses in a 3-phase 50 Hz 4-pole induction motor running at 1455 rpm are
300 W. The rotor input is
a) 5 kW b) 10 kW
c) 20 kW d) 50 kW
26. The no-load current of a 3-phase induction motor in terms of its full-load current is of the
order of
a) 5% b) 10%
c) 25% d) 50%
27. The power factor of a 3-phase induction motor at no load is approximately
a) 0.2 b) 0.7
c) 0.85 d) 1
28. The maximum torque in a 3-phase induction motor occurs at a slip
a) R2/ X2 b) X2/ R2
c) R22/ X2 d) R22/ X22
29. For high starting torque, the most 3-phase induction motor is
a) Squirrel-cage type
b) Slip-ring type
c) Deep bar squirrel-cage type
d) Double-cage induction motor
30. The starting torque in a single-phase induction motor is
a) High
b) Low
c) Zero
d) Very low

30. 31. The efficiency of a single-phase induction motor as compared to a 3-phase induction motor
rating is
a) Lower
b) Higher
c) Equal
32. The starting torque of a 3-phase induction motor can be increased by increasing
a) the rotor reactance b) the rotor resistance
c) the stator resistance d) None
33. The maximum starting torque in the induction motor is developed when the rotor reactance is
a) half of the rotor resistance
b) twice of the rotor resistance
c) equal to the rotor resistance
d) None
34. A change of 55 in the supply voltage of an induction motor will produce a change of
approximately in the rotor torque.
a) 5% b) 7% c) 10% d) 25%
35. The transformation ratio of an induction motor can be found by
a) blocked rotor test
b) open circuit test
c) slip test
d) stator resistance test
36. The crawling in the induction motor is caused by
a) improper design of the machine
b) low supply voltage
c) high loads
d) harmonics developed in the motor.

31. 37. Which one of the following motors is most suitable for signalling devices and timers?
a) dc series motor b) ac series motor
c) induction motor d) reluctance motor
38. The frequency of voltage generated by an alternator having 4-poles and rotating at 1800
r.p.m. is .......hertz.
(a) 60 (b) 7200
(c) 120 (d) 450
39. A 50-Hz alternator will run at the greatest possible speed if it is wound for ....... poles.
(a) 8 (b) 6
(c) 4 (d) 2
40. The main disadvantage of using short-pitch winding in alternators is that it
(a) Reduces harmonics in the generated voltage
(b) Reduces the total voltage around the armature coils
(c) Produces asymmetry in the three phase windings
(d) Increases Cu of end connections.
41. In an alternator, voltage drops occurs in
(A) Armature resistance only
(B) Armature resistance and leakage reactance
(C) Armature resistance, leakage reactance and armature reaction
(D) Armature resistance, leakage reactance, armature reaction and earth connections.
42. The magnitude of various voltage drops that occur in an alternator, depends on
(A) power factor of the load
(B) load current
(C) power factor x load current
(D) power factor x (load current)2.

32. 43. In an alternator, at lagging power factor, the generated voltage per phase, as compared to that
at unity power factor
(A) must be same as terminal voltage
(B) must be less than the terminal voltage
(C) must be more than the terminal voltage
(D) must be 1.41 time the terminal voltage.
44. The power factor of an alternator depends on
(A) Load
(B) Speed of rotor
(C) Core losses
(D) Armature losses.
45. Which kind of rotor is most suitable for turbo alternators which arc designed to run at high
speed ?
(A) Salient pole type
(B) Non-salient pole type
(C) Both (A) and (B) above
(D) None of the above.
46. Salient poles are generally used on
(A) high speed prime movers only
(B) medium speed prime movers only
(C) low speed prime movers only
( D) low and medium speed prime movers.
47. The frequency of voltage generated in an alternator depends on
(A) number of poles (B) rotative speed
(C) number of poles and rotative speed
(D) number of poles, rotative speed and type of winding.

33. 48. The frequency of voltage generated by an alternator having 8 poles and rotating at 250 rpm is
(A) 60 Hz
(B) 50 Hz
(C) 25 Hz
(D) 16 2/3 Hz.
49. An alternator is generating power at 210 V per phase while running at 1500 rpm. If the need
of the alternator drops to 1000 rpm, the generated voltage per phase will be
(A) 180 V
(B) 150 V
(C) 140 V
(D) 105 V.
50. A 10 pole AC generator rotates at 1200 rpm. The frequency of AC voltage in cycles per
second will be
(A)120
(B) 110
(C) 100
(D) 50.
KEY
1)B 2)A 3)A 4)A 5)A 6)B 7)C 8)A 9)A 10)A
11)B 12)B 13)B 14)C 15)A 16)C 17)B 18)B 19)C 20)D
21) A 22) B 23) C 24) A 25) B 26)A 27)A 28)A 29)B 30)C
31)A 32)B 33)C 34)D 35)A 36)D 37)D 38)A 39)D 40)B
31)C 32)B 33)C 34)A 35)B 36)D 37)C 38)D 39)C 40)C