Worksheetsunit 2
Total questions: 116
Worksheet time: 58mins
Name
Class
Date
1.
The current in a wire................
a)
Depends only on the resistance of the wire
b)
Depends on both resistance and potential difference
c)
Depends only on potential difference applied
d)
Does not depend on resistance and potential difference
2.
Four cells each of e.m.f "E" are joined in parallel to form a battery. The equivalent e.m.f of the battery will be..............
a)
E/4
b)
E=0
c)
4 E
d)
E
3.
One kilowatt hour of electrical energy is the same as…………
a)
36 x 10 ^5 B.T.U
b)
36 x 10 ^5 joules
c)
36 x 10 ^5 watts
d)
36 x 10 ergs
4.
Three 3 ohm resistors are connected to form a triangle. What is the resistance between any two of the corners?
a)
2 ohms
b)
3/4 ohms
c)
4/3 ohms
d)
3 ohms
5.
In the Internation System of Units, the unit of conductance is…………..
a)
Volt
b)
Farad
c)
Ohm
d)
Siemens
6.
The power factor is a ratio of…………..
a)
Reactive power to apparent power
b)
Real power to reactive power
c)
Real power to apparent power
d)
Reactive power to real power
7.
The instantaneous values of a sinusoidal waveform is given by the following formula:
a)
Vi=V_max tg t
b)
Vi=V_max sin t.cos t
c)
Vi=V_max sin t
d)
Vi=V_max cos t
8.
A circuit contains two un-equal resistances in parallel.
a)
current is same in both
b)
large current flows in larger resistor
c)
smaller resistance has smaller conductance
d)
potential difference across each is same
9.
For any node in ........, the sum of currents flowing into that node is equal to the the sum of currents flowing out of that node, or equivalently:
a)
Counter
b)
Electric power plant
c)
An winding
d)
An electricial circuit
10.
Assume an electric network consisting of two voltage sources and three resistors:
a)
i1 + i2 - i3=0
b)
i1 - i2 - i3=0
c)
i1 + i2 + i3=0
d)
-i1 - i2 + i3=0
11.
The Hertz is defined as:
a)
Minutes per cycle
b)
Cycles per one second
c)
Cycles per one minute
d)
Seconds per cycle
12.
A coil of inductance 150mH and zero resistance is connected across a 100V, 50Hz sypply. The inductive reactance of the coils:
a)
41,72 Ω
b)
41,17 Ω
c)
41,12 Ω
d)
47,1 Ω
13.
A coil of inductance 150mH and zero resistance is connected across a 100V, 50Hz sypply. The current flowing through the reactance is:
a)
2,12 A
b)
2,72 A
c)
2,21 A
d)
2,27 A
14.
A coil which has a resistance of 22 is connected to a 20 V DC supply. Which is the value of the current?
a)
1 A
b)
0 ,1A
c)
100 A
d)
10 A
15.
A coil which has an inductance of 40mH and a resistance of 22 is connected together to form a LR series circuit. If they are connected to a 20V DC supply. Which is the final steady state value of the current?
a)
1 A
b)
0 ,1A
c)
100 A
d)
10 A
16.
Calculate the capacitive reactance value of a 110 nF capacitor at a frequency of 1kHz:coil of inductance 150mH and zero resistance is connected across a 100V, 50Hz sypply. The current flowing through the reactance is:
a)
723,4 Ω
b)
734,2 Ω
c)
744,2 Ω
d)
732,2 Ω
17.
What will be the value of a capacitor in farads when it has a capacitive reactance of 2002 and is connected to a 50Hz supply:
a)
15,29 µF
b)
12,59 µF
c)
15,22 µF
d)
15,92 µF
18.
In the alternative current circuit, which of following statements is correct:
a)
The voltage across a capacitor lags the current by 90 °
b)
The voltage across a capacitor leads the current by 90 °
c)
The voltage across a capacitor is in phase with the current.
d)
The current flowing through a capacitor lags the voltage by 90
19.
Which of the following statements is true?
a)
Power is proportional to voltage only
b)
Power is proportional to current only
c)
Power is neither proportional to voltage nor to the current
d)
Power is proportional to both the voltage and current
20.
Calculate the quantity of electricity flows through a circuit carrying a current of 10 A in 1 minute?
a)
10 C
b)
60 C
c)
600 C
d)
1200 C
21.
The unit of resistivity (p) is
a)
Ω
b)
Ω.m
c)
Ω/m
d)
Ω/m²
22.
Which quantity should be measured by the voltmeter?
a)
Current
b)
Voltage
c)
Power
d)
Turbine speed
23.
What does the flow of electrons refer to?
a)
Insulator
b)
Electric current
c)
Semiconductor
d)
Voltage
24.
Which of the following materials has the largest resistance?
a)
Superconductor
b)
Semiconductor
c)
Conductor.
d)
Insulator:
25.
What is meant by the time rate of change of charge?
a)
Electric current
b)
Electric potential
c)
Electric resistance
d)
Electric power
26.
What is the unit of potential difference?
a)
Ohm
b)
Volt
c)
Watt
d)
Ampere
27.
What is the absolute value of charge of an electron?
a)
1.6022 x 10 ^(-19) Coulomb
b)
6.25 x 10 ^(-27) Coulomb
c)
9.1 x 10 ^(-31) Coulomb
d)
1.6022 x 10 ^(-21) Coulomb
28.
What is the SI unit of electric current?
a)
Ampere
b)
Ohm
c)
Volt
d)
Watt
29.
What is the rated frequency of Vietnam power system?
a)
50 Hz
b)
60 Hz
c)
100 Hz
d)
220 Hz
30.
Ampere second is the unit of
a)
Conductance
b)
Power
c)
Energy
d)
Charge
31.
What will be the resistance if 10 resistors of 10 ohm each are connected in series?
a)
1000
b)
1Ω
c)
0.1Ω
d)
10Ω
32.
The resistance of 200 W, 200 VDC lamp is
a)
100Ω
b)
200Ω
c)
300Ω
d)
400Ω
33.
The unit of capacitance is
a)
Farad
b)
Coulomb
c)
Henry
d)
Weber
34.
Which of the following quantities remain the same in all parts of a parallel circuit.
a)
current
b)
voltage
c)
resistance
d)
power
35.
Which of the following formula is NOT an expression of power?
a)
P=VI
b)
P=I^2.R
c)
P=V^2/R
d)
P=I/R
36.
The resistivity (p) of the conductor depends on
a)
area of the conductor.
b)
length of the conductor.
c)
type of material
d)
none of these
37.
Reactive power drawn by a pure resistor is
a)
Zero
b)
Minimum
c)
Maximum
d)
None of the above
38.
If a current of 1 A flows in a circuit, the number of electrons flowing through this circuit in 1 second is:
a)
6,24 x 10 ^18
b)
1,6 x 10 ^18
c)
1,6 x 10 ^(-18)
d)
0,625 x 10 ^(-18)
39.
Three 60 W bulbs are connected in parallel, supplied by a
DC source of 60 V. If one bulb burns
a)
there will be heavy current in the main line
b)
rest of two bulbs will not light.
c)
all three bulbs will light.
d)
the other two bulbs will light.
40.
What is the calculation of apparent power in a single-phase sinusoidal circuit at steady state?
a)
Product of voltage and current.
b)
Product of rms voltage and rms current.
c)
Product of voltage and current at no load
d)
Product of voltage and current at full load.
41.
The unit of the active power is
a)
Watt-Hour
b)
Volt-Ampere Reactive
c)
Watt
d)
Volt-Ampere
42.
The unit of the reactive power is
a)
Watt-hour
b)
Watt
c)
Volt-Ampere Reactive
d)
Volt-Ampere
43.
The unit of the apparent power is
a)
Watt-hour
b)
Watt
c)
Volt-Ampere
d)
Volt-Ampere Reactive
44.
The unit of electric resistance is
a)
Siemens
b)
Tesla
c)
Ohm
d)
Coulomb
45.
The unit of charge is
a)
Siemens
b)
Tesla
c)
Coulomb
d)
Ohm
46.
The unit of conductance is
a)
Ohm
b)
Tesla
c)
Siemens
d)
Coulomb
47.
Ampere is the unit of
a)
Impedance
b)
Voltage
c)
Current
d)
Energy
48.
Ohm is the unit of
a)
Current
b)
Voltage
c)
Impedance
d)
Energy
49.
Joule is the unit of
a)
Impedance
b)
Voltage
c)
Energy
d)
Current
50.
Volt is the unit of
a)
Electric Circuit
b)
Electric Current
c)
Potential Difference
d)
Volt-meter
51.
Volt is the unit of
a)
Reactive Power
b)
Active Power
c)
Voltage
d)
Impedance
52.
Ampere is the unit of
a)
Electric Circuit
b)
Voltage
c)
Electric Current
d)
Volt-meter
53.
Write out V1 = V2 + V3 in full
a)
Voltage one equals Voltage two plus Voltage three
b)
V one equal to V two plus V three
c)
V one equals V two plus V three
d)
Voltage one equals Voltage two minus Voltage three
54.
Write out V2 + V3 = V1 in full
a)
Voltage two plus Voltage three is equal to Voltage three
b)
V one equals V two plus V three
c)
V two plus V three is equal to V one
d)
V two plus V three equal to V one
55.
Z is the symbol of
a)
Resistance
b)
Reactance
c)
Impedance
d)
Energy
56.
R is the symbol of
a)
Impedance
b)
Reactance
c)
Resistance
d)
Energy
57.
X is the symbol of
a)
Impedance
b)
Resistance
c)
Reactance
d)
Energy
58.
W is the symbol of
a)
Impedance
b)
Reactance
c)
Energy
d)
Resistance
59.
L is the symbol of
a)
Impedance
b)
Reactance
c)
Inductance
d)
Capacitance
60.
C is the symbol of
a)
Impedance
b)
Reactance
c)
Capacitance
d)
Inductance
61.
The symbol of impedance is
a)
X
b)
L
c)
Z
d)
R
62.
The symbol of reactance is
a)
Z
b)
X
c)
L
d)
R
63.
The symbol of resistance is
a)
Z
b)
L
c)
R
d)
X
64.
The symbol of inductance is
a)
Z
b)
X
c)
L
d)
R
65.
The symbol of electric current is
a)
Z
b)
V
c)
I
d)
P
66.
The symbol of potential difference is
a)
Z
b)
I
c)
V
d)
P
67.
The symbol of active power is
a)
S
b)
Q
c)
P
d)
W
68.
The symbol of reactive power is
a)
S
b)
P
c)
Q
d)
W
69.
The symbol of apparent power is
a)
P
b)
Q
c)
S
d)
W
70.
The symbol of energy is
a)
P
b)
Q
c)
W
d)
S
71.
A source e.m.f of 5V provides a current of 5A for 1 minute. How much energy is provided in this time?
a)
250 J
b)
150 J
c)
1.5 kJ
d)
25 J
72.
A resistance of 5kΩ has a conductance of?
a)
2 S
b)
0.2 kS
c)
0.2 mS
d)
2 mS
73.
Write out R2 + 15Ω = R1 in full
a)
Resistance two plus fifteen ohms equals resistance one.
b)
R one minus R two equals fifteen ohms.
c)
R two plus fifteen ohms is equal to R one.
d)
R two plus fifteen multiplied by ohm is equal to R one.
74.
One…….. is defined as the difference in potential between two points in a conductor which, when carrying a current of one ampere, dissipates a power of one watt.
a)
volt
b)
watt
c)
current
d)
coulomb
75.
Write out R2 + 15 Ω = R1 in full
a)
Resistance two plus fifteen ohms equals resistance one.
b)
R one minus R two equals fifteen ohms.
c)
R two plus fifteen ohms is equal to R one.
d)
R two plus fifteen multiplied by ohm is equal to R one.
76.
"The sum of I one, I two, and I three equals I four" is the full expression of
a)
I+ I2 & I3 = I4
b)
I4=I1 +I2 + I 3
c)
I1 +I2 +I3= I4
d)
I +I +I +2 +I +3 = I 4
77.
"I one plus I two equals four fifths of 1 three" is the full expression of
a)
I1 +I2 = (5 /4).I 3
b)
I1 +I2 = (4 /5).I 3
c)
(4/5).I3=I1 + I 2
78.
Write out P = VIcos in full
a)
The active power equals the product of the voltage, the current, and power factor.
b)
P equals to the product of V, I, and cos .
c)
P equals the product of V, I, and cos .
d)
P equals the product of V, I, c, o, s, and .
79.
Write out Y = 1/Z in full
a)
The reciprocal of Z is equal to Y.
b)
Z is equal to the reciprocal of Y.
c)
Y is equal to the reciprocal of Z.
d)
The admittance is equal to the reciprocal of the impedance.
80.
Write out Z = 1/Y in full
a)
The reciprocal of Y is equal to Z.
b)
Y is equal to the reciprocal of Z.
c)
Z is equal to the reciprocal of Y.
d)
The impedance is equal to the reciprocal of the admittance.
81.
Write out Q = VIsin in full
a)
The reactive power equals the product of the voltage, the current, and sino.
b)
Q equals to the product of V, I, and sin
c)
Q equals the product of V, I, and sin
d)
Q equals the product of V, I, s, i, n, and
82.
What is the unit of the apparent power?
a)
Ampere
b)
Watt
c)
Volt-Ampere
d)
Volt
83.
What is the unit of the active power?
a)
Ampere
b)
Volt-Ampere
c)
Watt
d)
Volt
84.
What is the unit of the reactive power?
a)
Ampere
b)
Volt-Ampere
c)
Volt-ampere reactive
d)
Volt
85.
Which is the symbol of Reactive power?
a)
P
b)
S
c)
Q
d)
E
86.
Whích is the symbol of Active power?
a)
Q
b)
S
c)
P
d)
Z
87.
What is the unit of frequency?
a)
Ampere
b)
Volt-Ampere
c)
Hertz
d)
Volt
88.
The Ohm is the unit of the:
a)
Capacitance
b)
Capacitor
c)
Capacitive reactance
d)
Apparent power
89.
The Henry is the unit of the:
a)
Resistance
b)
Capacitance
c)
Inductance
d)
Conductance
90.
The Farad is the unit of:
a)
Resistance
b)
Inductance
c)
Capacitance
d)
Conductance
91.
A battery of e.m.f of 12 V supplies a current of 10 A for 6 minutes. How much energy is supplied in this time?
a)
12 VAh
b)
720 VAh
c)
7200 VAh
d)
20 Vah
92.
A current of 5 A flows through a conductor and 10 W dissipated. What voltage exists across the ends of the conductor?
a)
2 V
b)
50 V
c)
0,5 V
d)
0,2 V
93.
A conductor has a conductance of 0.1 S. It's resistance is:
a)
10Ω
b)
1Ω
c)
0.1 Ω
d)
1 m Ω
94.
A conductor has a resistance of 10Ω. It's conductance is:
a)
0.1 S
b)
10 S
c)
0 ,1mS
d)
1 S
95.
What is the unit of electromotive force?
a)
Coulomb
b)
Volt
c)
Ohm
d)
Ampere
96.
What does the "potential difference" mean?
a)
A change in resistance between two points in an electric circuit.
b)
A change in power between two points in an electric circuit.
c)
A change in electric current between two points in an electric circuit.
d)
A change in electric potential between two points in an electric circuit.
97.
A change in electric potential between two points in an electric circuit.
a)
The ratio of apparent power to reactive power.
b)
The ratio of apparent power to active power.
c)
The ratio of reactive power to apparent power.
d)
The The ratio of active power to apparent power.
98.
What is the unit of mutual inductance?
a)
Farad
b)
Siemens
c)
Ohm
d)
Henry
99.
What is the rated frequency of Vietnam electric power system?
a)
32 GW
b)
400 V
c)
500 kV
d)
50 Hz
100.
The basic unit of electric power is……. a which is a rate of producing or consuming energy.
a)
watt
b)
newton
c)
voltage
d)
ohm
101.
Ohm's Law gives a relationship between the current through a resistor and the ……… across the resistor.
a)
voltage
b)
power
c)
impedance
d)
inductance
102.
......is defined as the rate of doing work or transferring energy
a)
Voltage
b)
Current
c)
Power
d)
Energy
103.
A kilowatt is roughly equivalent to 1.3.........
a)
electric power
b)
horsepower
c)
electricity
d)
power
104.
To wedge a 25g steel key through a distance of 100 mm with an acceleration of 0.1 m/s² we use a rawhile mallet. What is the work done?
a)
2,5 kJ
b)
0,25 kJ
c)
25 kJ
d)
25 J
105.
Cooper is a material which creates an easy pass for electric.........?
a)
Energy
b)
power
c)
current
d)
voltage
106.
The…….. is defined as the work done or energy transferred when a force of one newton is exerted through a distance of one metre in the direction of the force
a)
volt
b)
newton
c)
joule
d)
ampere
107.
Active power (P) is calculated from a trigonometric function, the production of voltage (V), current (I) and cosine of the phase angle (coso). The formula for true power is:
a)
P = V/ I. cos
b)
P = √V.I. coso
c)
P = V.I.cos
d)
P = √V.I. cos
108.
In a purely reactive circuit, either inductive or capacitive, no power (P = V.I. cos) is consumed because of .......
a)
current and voltage are 45 degrees out of phase
b)
current and voltage are 0 degrees out of phase
c)
current and voltage are 90 degrees out of phase
d)
current and voltage are 180 degrees out of phase
109.
In order that....may be done, a supply of energy is required.
a)
voltage
b)
work
c)
force
d)
current
110.
A current of 4A flows for 10h through a 100Ω resistor. The energy consumed by the resistor is?
a)
0,16 kWh
b)
16 kWh
c)
4 kWh
d)
32 kWh
111.
Four cells each of e.m.f 'E' are joined in parallel to form a battery. The equivalent e.m.f of the battery will be.......
a)
4 E
b)
E
c)
2 E
d)
E/2
112.
In what time would a current of 5 A transfer a charge of 30 C?
a)
6 ms
b)
6 s
c)
60 ms
d)
600 ms
113.
Determine the force acting downwards on a mass of 1500g suspended on a string?
a)
14.715 kN
b)
14.715 N
c)
147.15 KN
d)
147.15 N
114.
A dc electric motor consumes 36 MJ when connected to a 250 V supply for 1 hour. Find the power rating of the motor and the current taken from the supply?
a)
14.4 kW, 57.6 mA
b)
10 kW, 40 A
c)
10 W, 40 mA
d)
144 W, 0.576 A
115.
An electrical hoist can raise a 300 kg electric motor to a height of 5 metres in 10 seconds against the force of gravity. What is the power developed?
a)
1471.5 kW
b)
150 kW
c)
1471.5 W
d)
150 W
116.
An electrical fitter has to fit a steel key to the shaft of a rotor in order to fit a sprocket. What force is required to wedge the 25 g key mass through a distance of 100 mm with an acceleration of 0.1 m/s² using a rawhide mallet?
a)
250 mN
b)
25 mN
c)
2.5 mN
d)
0.25 mN
100 %
