Concepts of DC Final Exam Review
A series circuit has a total resistance of 240 Ω and a current flow of 4 A. What is the applied voltage? a) 244v b) 60v c) 0.0167v d) 960v
d) 960v
A method for finding total resistance of parallel resistors is _____. a) product over sum b) reciprocal formula c) resistors of equal value d) all the above
d) all the above
What type of resistors are generally used when a high power rating is needed? a) carbon film b) metal glaze c) wire wound d) metal film
c) wire wound
What is indicated by the fourth color band on a four color band resistor? a) tolerance b) multiplier c) number values d) divider
a) tolerance
In a series circuit, the _______________ is the sum of the individual resistances. a) total resistance b) total power c) total voltage d) none
a) total resistance
the amount of ____ across a resistor is proportional to its resistance a) voltage drop b) voltage rise c) current drop d) current rise
a) voltage drop
A three-branch parallel circuit has a total resistance of 385.83 Ω. Resistor #1 equals 680 Ω resistor #2 equals 1500 Ω. What is the value of the third resistor? a) 2180 ohm b) 2200 ohm c) 467.89 ohm d) 246.16 ohm
b) 2200 ohm
In series circuits, the _____ is the same at any point in the circuit. a) resistance b) current c) voltage drop
b) current
An electrical circuit has a voltage of 50 V and a resistance of 5 Ω. What is the value of current? a) 10A b) 45A c) 55A d) 250A
a) 10A
A toaster is listed as 1560 W. When it is plugged into a 120 V circuit and starts to make toast, how many amperes will it draw? a) 13 b) 1440 c) 1680 d) 187,200
a) 13
Parallel circuits are also referred to as _____. a) current dividers b) current multipliers c) voltage dividers d) voltage multipliers
a) current dividers
The Most Important Rule of Safety is: a) to think b) avoid horseplay c) don't work alone d) learn first aid
a) to think
The _____ of a resistor indicates the plus and minus limits of a resistor's ohmic value. a) tolerance b) resistance c) coefficient d) wattage
a) tolerance
What force pushes the electrons through a resistance in a circuit? a) voltage b) inductance c) power d) current
a) voltage
When a circuit has only one path, the _____ is the same at any point. a) voltage b) current c) power d) resistance
b) current
In a parallel circuit, the total resistance is _____ branch resistor value. a) larger than the lowest b) less than the lowest c) equal to the largest d) equal to the lowest
b) less than the lowest
what part of an atom has no charge a) quark b) neutron c) proton d) electron
b) neutron
There is very little resistance and a large amount of current flows in a(n) _____ circuit. a) open b) long c) short d) none
c) short
in a parallel circuit the total current flow is equal to the ______ of the currents through all the branches a) difference b) average c) sum d) quotient
c) sum
A series circuit has a total resistance of 180 Ω and an applied voltage of 120 V. What is the current flow? a) 300A b) 1.5A c) 60A d) 0.667A
d) 0.667A
An electric circuit has a resistance of 20 Ω. The current is measured to be 6 A. How many volts are applied to the circuit? a) 3 1/3 b) 14 c) 26 d) 120
d) 120
A parallel circuit is composed of two branches with one 60 Ω resistor in each branch. What is the total resistance? a) 1 ohm b) 3600 ohm c) 120 ohm d) 30 ohm
d) 30 ohm
A three branch parallel circuit has resistors of 27 Ω, 56 Ω, and 15 Ω. What is the total resistance? a) 9.64 ohm b) 98 ohm c) 18.22 ohm d) 8.32 ohm
d) 8.32 ohm
What is another term for electromotive force (EMF)? a) amperage b) ohmage c) voltage d) wattage
c) voltage
Adhering to the practice of always disconnecting or turning supply source off before changing range on meter will result a) longer meter life b) better reliability of meter c) less fuse blowing d) all the above
d) all the above
A three-resistor circuit has a total power of 25 W. Two of the resistors dissipate 10 W and 5 W, respectively. How much power does the third resistor dissipate? a) 25w b) 10w c) 2w d) 15w
b) 10w
What is the applied voltage in a series circuit with two resistors (25 V and 60 V, respectively)? a) 35v b) 85v c) 25v d) 60v
b) 85v
When the approximate value of voltage or current being measured is not known: a) Always start at the lowest range setting on meter to avoid blowing a fuse b) Always start at the highest range setting on meter to avoid blowing a fuse c) Do not worry about range because there is a fuse to protect the meter from damage d) none
b) Always start at the highest range setting on meter to avoid blowing a fuse
To measure voltage in a circuit you must make your measurement a) in series with component to be measured b) across the component to be measured
b) across the component to be measured
A two-resistor series circuit has an applied voltage of 100 V. The voltage across one of the resistors is 40 V. What is the voltage across the other resistor? a) 0.4v b) 2.5v c) 60v d) 140v
c) 60v
A combination circuit is a circuit that contains _____. a) only series components b) only parallel components c) both series and parallel components d) both voltage and current sources
c) both series and parallel components
What is the maximum number of valence electrons in an atom? a) four b) six c) eight d) twelve
c) eight
An insulator is an element containing _____ valence electrons in the outer shell of its atom. a) one or two b) three or four c) five or six d) seven or eight
d) seven or eight
The amount of electrical power being used in a circuit is measured in ____. a) amperes b) volts c) ohms d) watts
d) watts
TRUE or FALSE: When zeroing meter before making resistance measurements you should always make sure you can see a reflection of the meter's needle in the mirror on the face of the meter true false
false
the amount of current flowing in a series circuit through each resistor is directly proportional to individual resistance values true false
false
In a parallel circuit, the voltage across each branch must be equal to supply voltage true false
true
Most devices such as light receptacles in homes and office buildings are connected in parallel circuits. true false
true
Never work on an energized circuit if power can be disconnected. true false
true
The ohm value of a carbon composite resistor can be determined by the "color code." true false
true
If a series circuit has resistor values of 27 Ω, 56 Ω, and 82 Ω, the total resistance is _______________ Ω. a) 165 b) 200 c) 16.5 d) 1650
a) 165
how many color bands are used on resistors that have a tolerance of +/- 20 percent? a) 3 b) 4 c) 5 d) 6
a) 3
An electric motor is running on 120 V. The current is measured to be 2 A. How many ohms of resistance is the motor? a) 60 b) 118 c) 122 d) 240
a) 60
A parallel circuit has a 10 Ω branch and a 22 Ω branch. The circuit has a supply voltage of 60 V. What is the current in the 10 Ω resistor? a) 6A b) 5A c) 2.73A d) 1.88A
a) 6A
One coulomb per second is equal to one _____. a) ampere b) ohm c) volt d) watt
a) ampere
In parallel circuits, the voltage drop across any branch is the same as the _____. a) applied voltage b) current c) resistance
a) applied voltage
what force is demonstrated in objects with unlike charges a) attraction b) repel
a) attraction
a complete circuit is often referred to as a ____ circuit a) closed b) open c) shorted d) grounded
a) closed
The term "load" refers to the amount of _____ in a circuit branch. a) current b) resistance c) voltage d) wattage
a) current
what device is designed to open and disconnect a circuit in the event of excessive current? a) fuse b) power supply c) wire d) potentiometer
a) fuse
To measure current in a circuit you must make your measurement: a) in series with component to be measured b) across the component to be measured
a) in series with component to be measured
A variable resistor with three terminals is called a _____. a) multi-turn resistor b) potentiometer c) wire wound resistor d) rheostat
b) potentiometer
A basic law of physics states that like charges _____ and opposite charges _____. a) attract, repel b) repel, attract c) combine, counteract d) counteract, combine
b) repel, attract
What force is demonstrated in objects with like charges? a) attraction b) repulsion
b) repulsion
A resistor whose values can be varied over a range of values is called a _____ resistor. a) fixed b) variable c) carbon d) wire wound
b) variable
a series circuit has 2 resistors that dissipate 10w and 15w respectively. what is the total power dissipation of the circuit a) 10w b) 5w c) 25w d) 15w
c) 25w
What standard prefix in engineering notation indicates multiplication by 1,000,000,000? a) kilo K b) tera T c) giga G d) mega M
c) giga G
What is the most common method of producing electricity? a) chemicals b) friction c) magnetism d) light
c) magnetism
The nucleus of an atom contains _____. a) electrons and protons b) electrons and quarks c) neutrons and protons d) neutrons and quarks
c) neutrons and protons
The current, voltage, power, and resistance in a series circuit can be calculated using _____ law. a) ampers b) coulombs c) ohms d) volts
c) ohms
the statement "in a DC circuit, the current is directly proportional to voltage and inversely proportional to resistance" is know as ___ law a) amperes b) coulombs c) ohms d) volts
c) ohms
What part of an atom has a positive charge? a) quark b) neutrons c) proton d) electron
c) proton
A voltage _____ is used to provide different voltages between certain points in a circuit. a) doubler b) multiplier c) scalar d) divider
d) divider
What part of an atom has a negative charge? a) quark b) neutron c) proton d) electron
d) electron
Electrical current is the flow of _____. a) quarks b) neutrons c) protons d) electrons
d) electrons
What color used as the multiplier band means to divide the combined first two numbers by 10? a) violet b) red c) silver d) gold
d) gold
Solving combination circuits (series-parallel) includes steps in which you _____. a) enlarge the circuit to several combination circuits b) eliminate all parallel paths c) expand the circuit to a more complex circuit d) reduce the circuit to a simpler circuit
d) reduce the circuit to a simpler circuit
A variable resistor with two terminals is called a _____. a) multi-turn resistor b) potentiometer c) wire wound resistor d) rheostat
d) rheostat
The total Current in a parallel circuit is equal to the sum of the currents through all of the circuit branches. true false
true
Work with one hand when possible: Electric shock can be fatal when traveling from hand to hand because the current path can be through the heart. true false
true
If a circuit is open, current _____ flow. will will not
will not
A series circuit has _____ path(s) for current flow. a) one b) two c) three d) unlimited
a) one
A conductor is made from an element that contains between _____ electrons in the outer shell of its atom. a) one and three b) two and four c) three and five d) four and six
a) one and three
circuits that have more than one path for current flow are ___ circuits a) parallel b) series
a) parallel
conventional current flow theory states that current flows from the most..... a) positive point to the most negative b) negative point to the most positive
a) positive point to the most negative
what is another term for a variable resistor a) potentiometer b) wire wound resistor c) metal film resistor
a) potentiometer
A circuit that has only one path for current flow is a _____ circuit. a) series b) parallel
a) series
the unit of resistance to current flow is the ___ a) ampere b) ohm c) volt d) watt
b) ohm
The valence shell of an atom is the _____ shell. a) inner b) outer c) middle d) bottom
b) outer
By observing the direction of current flow through the circuit, voltage _____ can be determined. a) drop b) polarity
b) polarity
What are the three principle parts of an atom? a) electron, proton, and quark b) neutron, positron, and electron c) electron, neutron, and proton d) neutron, quark, and electron
c) electron, neutron, and proton
in a series circuit the sum of the voltage drops is _____ the applied voltage a) greater than b) less than c) equal to d) unrelated to
c) equal to
The amount of potential necessary to cause one coulomb to produce one joule of work is a(n) _____. a) ampere b) ohm c) volt d) watt
c) volt