WorksheetsAC/DC review for final exam
Total questions: 71
Worksheet time: 36mins
The flow of electrons across a conductor is known as....
Electricity
Voltage
Resistance
Power
What is the device used to transfer AC only but at different value?
Inductor
Resistor
Capacitor
Transformer
Click on the name of the electrical current that goes only in one direction
Direct current
Alternating current
3 phase current
the rule for series connection in terms of voltage is
There is only one voltage in the circuit
The current is only one all over the circuit
The voltage splits in as many parts as many electronic elements are connected in series
The main parts of an atom are...
electron and proton
positive and negative
shell and nucleus
anode and cathode
the smallest part of the matter is known as
Atom
Current
Electricity
Resistor
Electrons are found in the ______ of the atom
nucleus
Shell
core
body
The pressure or force that cause electrons to flow across a conductor is know as
Current
voltage
Resistance
period
The device that converts chemical energy to electrical energy is known as _______
Power supply
Battery
transistor
capacitor
The type of electrolyte used to make a wet cell battery is ______
Sulfuric acid and water
water
acid
fuel oil
Capacitor are elements used to control voltage in a circuit. which two information are printed on the body of the capacitor
voltage and current
Resistance and capacitance
voltage and capacitance
The basic uni for capacitance is
Farad
ohms
Hertz
Henry
The basic uni for resistance is
Farad
ohms
Hertz
Henry
The basic uni for period is
Farad
ohms
Hertz
second
The conventional frequency of the AC current in the Bahamas is
50 Hz
60 Hz
10 Hz
3.14 Hz
In Dc electronic circuits the current flows from _________
negative to positive
Positive to negative
North to south
The main formula for the ohm's law is
I = E/R
E = I x R
E = 2 FC
R = E/I
The basic unit of expressing power dissipated in electronic circuits is
Ohms
watts
volts
hertz
What color represents the number 6 in the resistor color code
Green
Red
blue
violet
A 50 ohms resistor has a silver tolerance band. what will be its maximum tolerance value?
55 ohms
45 ohms
60 ohms
40 ohms
The valence shell of the atom is always the: 1 Point
Outermost shell
Complete or filled shell
Shell with four electrons
innermost shell
A 12 volt battery is connected across two resistors in parallel. R1 = 1k ohm, R2= 2k ohm.
How much current will flow through R2. 2 Points
6mA
4mA
6A
10A
substance that has few free electrons is called an:
Conductor
Insulator
Coulomb
Compoud
A resistor has color bands of green, red, brown, and gold. What is the resistor
value and tolerance?
520 ohms +/- 5%
52 ohms +/- 5%
520 ohms +/- 10%
620 ohms +/- 5%
A
How much current will flow through a circuit if it has a resistance of 3 ohms
and an applied voltage of 12 volts?
6 A
12 A
4A
3A
A
If the resistance in a circuit is high, then:
Current will be low
Cyrrent stays the same
Current will be high
voltage stays the same
The fourth band of a 1 K ohm resistor is silver. The actual resistance may be
anywhere between:
1000 ohms and 1100 ohms
950 ohms and 1050 ohms
900 ohms and 1100 ohms
900 ohms and 1000 ohms
One milliampere is equal to: 1 Point
A) 0.001 amperes
B) 1000 amperes
C) 0.000001 amperes
D) 1000000 amperes
ANSWER: A
0.001 A
1000 A
0.000001 A
1000 000 A
A
What is the voltage drop across a 10K ohm resistor when the current through the
resistor is 1 mA?
10 V
100 V
1 Kv
10 Kv
A 50 micro farad capacitor is connected in parallel with a 100 micro farad capacitor.
What is the total capacitance?
150 micro farads
33.33 micro farads
66.66 micro farads
33.33 farads
One ampere is equal to:
0.001 microamperes
1000 microamperes
1000000 microamperes
0.000001 microamperes
A
A resistor = 10 k ohms is in series with a capacitor 20 micro farads connected to a 20 volt source.
What is the Time Constant of the circuit? 2 points
0.2 seconds
1 second
2 seconds
1.5 ms
A circuit with a resistor of 1 k-ohm and an inductor of 100 milli - Henry, has a
Time Constant:
10 s
0.001 ms
1 ms
0.1 ms
A
A 44 mH inductor is in series with a 102 mH inductor. What is the total
inductance?
30 mH
146 mH
50 mH
146 H
A 9 volt battery can be formed by connecting six 1.5 volt cells in a:
Series connection
series opposing
parallel
series - parallel
A
A series RL circuit has a resistor R1 = 50 ohms and an Inductor L = 2.5mHconnected to a 10 volt AC supply at 4Khz.
What will be the circuits True Power?
0.78 W
8 W
0.8 W
A
If the apparent power of a circuit is 5 watts and the true power is 4 watts,
then what is the Power Factor?
0.8
1
1.4
2
What is the true power consumed in an RLC circuit where the source is 60Hz/30v,
Z=20 ohms and R=10 ohms.
22.5 W
225 W
45 W
15 W
What is the total current in a parallel RLC circuit where IC=3A, IL=7A and IR=2A
6A
4.47A
3.61 A
7.62A
At resonance a circuit appears to be:
Resistive
Inductive
Capactive
None
In an RLC series resonant circuit, with R=500 ohms and XL=250 ohms, what would
be the value of XC?
200 ohms
0 ohms
500 ohms
250 ohms
A transformer is powered by a DC solar energy source which applies 120 v DC to
the primary winding. The turns ratio of the transformer is 20 : 4.
What will be the secondary output voltage?
0 V
1 V
30 V
8 V
A
A current sine wave with a peak value of 16 amps has an effective value of:
11.31 A
16 A
5.08 A
8 A
A sine wave with a period of 0.0125 seconds (12.5 ms) has a frequency of:
80 Hz
40 Hz
160 Hz
125 Hz
A
What is the impedance of a 60Hz/70v series RLC circuit if XL=10 ohms, R=33ohms
and XC=60ohms
60 ohms
72 ohms
55 ohms
83 ohms
Capacitors store electrical energy in the form of:
a Magnetic Field
an Electric Field
a Magnetic Field
Whenever the current flowing through an Inductor changes in magnitude or
direction:
The Inductor prohibits the production of its CEMF.
The inductor stores the additional energy provided as an electric field in
its coils.
The Inductor produces a CEMF to oppose the change.
A
In a parallel resistive circuit with a source voltage of 120v applied across two
resistors R1 = 1K ohms and R2 = 5K ohms,
the current flowing through R1 will be:
1.2mA
0.12mA
12mA
120mA
What is the total resistance in a circuit that has 9 resistors connected in
parallel, and each resistor is 8.1 kΩ ?
8.10 MΩ
900KΩ
16.2 kΩ
72.9 kΩ
A transformer with primary voltage higher then secondary voltage is known as:
Step up transformer
Step down transformer
power transformer
center tap transformer
In a series circuit with a 12V battery and two resistors R1 = 4Ω and R2 = 6Ω, what is the total current flowing through the circuit?
3 A
0.8 A
2 A
1.2 A
A capacitor has a capacitance of 10 microfarads. What is its reactance at a frequency of 1 kHz?
1590 Ω
15.9 kΩ
159 Ω
1.59 kΩ
What is the effective value of a current sine wave with a peak value of 20 amps?
5 A
14.14 A
10 A
20 A
In a series circuit, if one resistor fails, what happens to the current flow?
It stops
It remains the same
It decreases
It increases
What is the unit of measurement for inductance?
Volt
Ohm
Henry
Farad
What is the unit of measurement for capacitance?
Volt
Ohm
Henry
Farad
An atom that has lost a valence electron is called:
Positive ion
negative electron
neutron
nucleus
How many electrons are needed to produce one coulomb of charge?
6.28x1018
6.24x1018
6.28
3.14
In the series circuit with three resistors, the same magnitude of current flows through each resistor.
In the parallel circuit with two resistors of unequal values, the same voltage is applied across each resistor.
A transformer has the turns ratio NP:NS = 1:5; the Primary voltage is 100 V
20 V
500 V
250 V
100 V
A 20 mH inductor is used in a circuit with a source voltage of 115 V 50Hz.
6.3 Ω
63 Ω
6.28 Ω
15 Ω
A 10 µF capacitor is used in a circuit with a source voltage of 115 V 50 Hz.
Calculate the reactance.
318.3 Ω
100 Ω
10 Ω
In a pure resistive circuit:
The Voltage leads the Current
The Current leads the Voltage
The Voltage and the Current are in phase.
In a pure inductive circuit:
The Voltage leads the Current
The Current leads the Voltage
The Voltage and the Current are in phase.
In a pure resistive circuit:
The Voltage leads the Current
The Current leads the Voltage
The Voltage and the Current are in phase.
In a pure capacitive circuit:
The Voltage leads the Current
The Current leads the Voltage
The Voltage and the Current are in phase.
A generator’s was determined to have a peak-to-peak voltage: 325.27 V, 50 Hz.
Calculate the RMS voltage.
229.97 V
162.64 V
81.3 V
In the parallel circuit with two resistors of unequal values, the same current flows through each resistor.
Calculate the voltage across R2, if: R1 = 10 Ω; R2 = 100 Ω; R3 = 1 kΩ and the Battery is 9V z
811mv
1110 V
0.081 V
Calculate the voltage across R2, if: R1 = 2 kΩ; R2 = 3 kΩ; R3 = 6 kΩ and the Battery is 9V
6 v
9v
36 V
10 v
