ELEX 2 COCOON TESTS (Direct Current) Flashcards by Lyssa Anne Colombres

Which of the following is defined as Ohm’s Law?
a.) V=IR
b.) I=V/R
c.) R=V/I
d.) all of the choices

all of the choices

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Which of the following is not a urpose of a Resistor?
a.) produce voltage
b.) limit current
c.) develop voltage drop
d.) none of the above

produce voltage

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Which of the following is not a type of Resistor?
a.) carbon composition
b.) wire wound
c.) plastic film
d.) Carbon film

Plastic Film

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What is the resistance of a resistor having bands with colors: red red blue gold.
a.) 33 megaohms
b.) 22 megaohms
c.) 33 kiloohms
d.) 22 kiloohms

22Megaohms

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A resistor has a mark, 560R. What is its resistance?
a.) 560kiloohms
b.) 56 kiloohms
c.) 560 megaohms
d.) 560 ohms

560 ohms

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Five equal resistors are in series having a supply voltage of 15V. Find the voltage of each resistor.
a.) 5V
b.) 4V
c.) 9V
d.) 3V

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A VD has an R1 of 5 ohms and an R2 of 12 ohms. The supply voltage is 20V. Find the voltage across R1.
a.) 8.55 V
b.) 5.58 V
c.) 5.88 V
d.) 8.85 V

5.88 V

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Which of the following is true in parallel connected resistors?
a.) resistors are equal per branch
b.) current are equal per branch
c.) voltage are equal per branch
d.) power are equal per branch

voltage are equal per branch

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Which is true for current in a DC circuit?
a.) current divides in a series circuit
b.) current multiplies in a series circuit
c.) current remains the same in a series circuit
d. none of the choices

current remains the same in a series circuit

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In a circuit, the voltage is measured from point X to point Y. The voltage measured is:
a.) absolute voltage
b.) relative voltage
c.) both absolute and relative voltage
d.) none of the choices

relative voltage

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The algebraic sum of the currents going in and leaving any point in a circuit is equal zero. This belongs to:

Kirchhoff’s

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Which of the following is the 2nd Law of Kirchhoff’s?

KVL

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Using branch current method in analyzing DC circuits, when the solved current is negative, this means:
a.) the current has more electrons
b.) the current has more protons
c.) the current is in a correct direction
d.) the current is in the opposite direction

the current is in the opposite direction

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The Voltage across the branch is equal to the sum of all the brunch currents over the sum of all the branch conductance in a parallel circuit.
a.) Norton’s
b.) Thevenin’s
c.) Millman’s
d.) Kirchhoff’s

Millman’s

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A circuit simplification method which represents the circuit with a single voltage source and a series resistance.
a.) Norton’s
b.) Thevenin’s
c.) Millman’s
d.) Kirchhoff’s

Thevenin’s

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A circuit simplification method which represents the circuit with a single current source and a shunt resistance.
a.) Norton’s
b.) Thevenin’s
c.) Millman’s
d.) Kirchhoff’s

Norton’s

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The first step in Thevenizing a circuit is:
a.) short the source
b.) open the source
c.) short the load
d.) open the load

open the load

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In converting Thevenin to Norton:
a.) Vth = In
b.) Vth = Rth
c.) Rth = Rn
d.) Vth X In = Rth

Rth = Rn

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Which of the following is a unit of power.

J/s

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Which of the following is a unit of energy.
a.) A/s
b.) J/s
c.) C/s
d.) watt-hour

watt-hour

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Devices that stores electrical energy in an electrostatic field.
a.) inductance
b.) capacitor
c.) capacitance
d.) inductor

Capacitor

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In the construction of a basic capacitor, the _______ is in between the metallic plates.
a.) conductor
b.) dielectric
c.) terminals
d.) none of the choices

dielectric

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Electrostatic line of force:
a.) radiate in a straight line
b.) form into closed loops
c.) distort electron orbits
d.) both radiate in a straight line and distort electron orbits

both radiate in a straight line and distort electron orbits

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How do capacitors store electric energy?
a.) by distorting electron orbits
b.) by changing the polarity of the applied potential
c.) by allowing current to flow in the capacitor
d.) none of the choices

by distorting electron orbits

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Electric energy stored in the capacitor depends on: a.) the applied potential b.) inductance of the capacitor c.) magnetic field d.) the type of capacitor

the applied potential

The electrical size of the capacitor has a unit: a.) Henry b.) F/m c.) J/s d.) C/V

F/m

The capacitance of a capacitor which stores 5C of charge in a 5V potential is: a.) 1 C/s b.) 1 H c.) 1 F d.) 1 V/C

1 F

Capacitance depends in the following except: a.) distance between the plates b.) area of the plates c.) permeability of the dielectric d.) permittivity of the material between plates

permeability of the dielectric

To charge a capacitor: a.) a potential difference must exist on the plates b.) the capacitor terminals must be open c.) the capacitor terminals must be shorted d.) current must flow in the capacitor

A potential differennce must exist on the plates

Which of the following is directly proportional to capacitance? A. number of coil turns C. area of the plates B. length of the coil D. permeability

Area of the plates

To discharge a capacitor: a.) a potential difference must exists on the plates b.) the capacitor terminals must be open c.) the capacitor terminals must be shorted d.) current must flow in the capacitor

The capacitor terminals must be shorted

When three capacitors are connected in series, the total capacitance is: a.) the same as adding series resistances b.) the same as adding parallel capacitances c.) the same as adding parallel resistances d.) none of the choices

the same as adding parallel resistances

When seven capacitors are connected shunt, the total capacitance is: a.) the same as adding series resistances b.) the same as adding series capacitances c.) the same as adding parallel resistances d.) none of the choices

the same as adding series resistances

_________ are simply a coil of wire that introduces inductance in a circuit. a.) inductance b.) inductors c.) capacitance d.) capacitors

inductors

Inductors are made of: a.) dielectric materials b.) insulators c.) metal plates d.) conductor coils

conductor coils

Characteristic of an electrical circuit to oppose the change in current. a.) resistance b.) inductance c.) reactance d.) impedance

inductance

The value of 1H is equivalent to: a.) 1A/s change in current due to a changing 1V voltage b.) 1A current induced due to a changing voltage of 1V/s c.) 1V EMF induced due to a changing current of 1A/s d.) 1V per 1C

1V EMF induced due to a changing current of 1 A/s

The EMF is induced in the same circuit in which the current is changing. This describes: a.) inductance b.) mutual inductance c.) self inductance d.) transformer

Self inductance

Which of the following does not affect inductance? a.) number of turn b) diameter of the wire c.) length of the coil d.) permeability of the core

diameter of the wire

Which of the following affects inductance? a.) permeability of the coil b.) diameter of the wire c.) cross section area of the wire d.) permeability of the core

permeability of the core

Transformer action is an example of: a.) self capacitance b.) mutual inductance c.) self inductance d.) magnetism

mutual inductance

A coil needs to induce an EMF to another coil. If both coils have the same inductance and provided all flux in coil-1 links to coil-2, the mutual inductance is: a.) sum of the two inductances b.) product of the two inductances c.) inductance value of one coil d.) zero

inductance value of one coil

If no flux links from coil 1 to coil 22, the coefficient of coupling is: a.) infinite b.) 100 c.) 0 d.) 1

For series indductors with magnetic coupling, flux on both inductors may: a.) oppose each other b.) aid each other c.) oppose or aid each other d.) may cancel each other

oppose or aid each other

The energy stored in the magnetic field of an inductor is dependent on: a.) the capacitance of the inductor b.) the current through the coil c.) the inductance of the coil d.) both the current through the coil and the inductance of the coil.

both the current through the coil and the inductance of the coil

46-50: In the following items, please refer to the figure in the black notebook.

46.) 5.18 V 47.) 173 mA 48.) 9.82 V 49.) 2.82 V 50.) 28.2 mA

If two 4 ohms resistors are connected in series the effective resistance of the circuit is:

8 ohms

If two 4 ohms resistors are connected in parallel the effective resistance of the circuit is:

2 ohms

With the switch in Figure closed, the ammeter reading will indicate:

1/3 A

The effect of connecting an additional parallel load to an electrical supply source is to increase the

Voltage of the source

The equivalent resistance when a resistor of 1/3 ohms is connected in parallel with a 1/4 ohms resistance is:

1/7 ohms

A 10 ohm resistor is connected in parallel with a 15 ohm resistor and the combination in series with a 12 ohm resistor. The equivalent resistance of the circuit is: a.) 37 ohms b.) 18 ohms c.) 27 ohms d.) 4 ohms

18 ohms

When three 3 ohms resistors are connected in parallel, the total resistance is: a.) 3 ohms b.) 9 ohms c.) 1 ohm d.) 0.333 ohms

1 ohm

The total resistance of two resistors R1 and R2 when connected in parallel is given by: a.) R1 + R2 b.) 1/R1 + 1/R2 c.) (R1 + R2) / (R1 x R2) d.) (R1 x R2) / (R1 + R2)

(R1 x R2) / (R1 + R2)

If in a series circuit with a single resistance R and a supply V, the reading on the voltmeter across R is 5V and the reading on the ammeter is 25 mA, the resistance of resistor R is: a.) 0.005 ohms b.) 5 ohms c.) 125 ohms d.) 200 ohms

200 ohms

A carbon composition resistor having only three color stripes has a tolerance of a.) +/- 5% b.) +/- 20% c.) +/- 10% d.) +/- 100%

+/- 20%

When checked with an ohmmeter, an open resistor measures a.) infinite resistance b.) its color-coded value c.) zero resistance d.) less than its color-coded value

infinite resistance

A chip resistor is marked 394. Its resistance value is a.) 39. 4 ohms b.) 394 ohms c.) 390, 000 ohms d.) 39,000 ohms

390, 000 ohms

A potentiometer is a a.) three-terminal device used to vary the voltage in a circuit b.) two-terminal device used to vary the current in a circuit c.) fixed resistor d.) two-terminal device used to vary the voltage in a circuit

three-terminal device used to vary the voltage in a circuit

Which of the following resistors has the smallest physical size? a.) wire-wound resistors b.) carbon-composition resistors c.) surface-mount resistors d.) potentiometers

surface mount resistors

If a thermistor has a negative temperature coefficient (NTC), its resistance a.) increases with an increase in operating temperature b.) decreases with a decrease in operating temperature c.) decreases with an increase in operating temperature d.) is unaffected by its operating temperature

decreases with a increase in operating temperature

Which of the following axial-lead resistor types usually as a blue, light green, or red body? a.) wire-rounded resistors b.) carbon-composition resistors c.) carbon-film resistors d.) metal-film resistors

Metal-film resistors

metal-film resistors

Reading from left to right, the colored bands on a resistor are yellow, violet, brown and gold. If the resistor measures 513 ohms with an ohmmeter, it is a.) well within tolerance b.) out of tolerance c.) right on the money d.) close enough to be considered within tolerance

out of tolerance

In a series circuit, the current, I, is a.) difference in each resistor b.) the same everywhere c.) the highest near the positive and negative terminals of the voltage d.) different at all points along the circuit

the same everywhere

A 10 ohm and 15 ohm resistor are in series across a dc voltage source. If the 10 ohm resistor has a voltage drop of 12V, how much is the applied voltage? a.) 18V b.) 12V c.) 30V d.) The value of applied voltage cannot be determined

30V

A voltage of 120V is applied across two resistors, R1 and R2, in series. If the voltage R2 equals 90V, how much is the voltage across R1? a.) 90V b.) 30V c.) 120V d.) cannot be determined

30V

The notation VBG, means a.) the voltage at Point G with respect to B b.) the voltage at Point B with respect to G c.) the battery (b) or generator (G) voltage d.) none of the above

the voltage at Point B with respect to G

A 6V and 9V source are connected in a series-aiding configuration. How much is the net or total voltage? a.) -3V b.) +3V c.) 0V d.) 15V

15V

If a resistor in a series circuit becomes open, how much is the voltage across each of the remaining resistors that are still good? A. Each good resistor has the full value of applied voltage B. The applied voltage is split evenly amongst the good resistors C. 0 V D. This is impossible to determine

The schematic symbol for earth ground is A. B. C. D.

If one branch of a parallel circuit becomes open, a.) all remaining branch currents increase b.) the voltage across the open branch will be 0V c.) the remaining branch currents do not change value d.) the equivalent resistance of the circuit decreases

the remaining branch currents do not change value

If the fuse in the main line of a parallel circuit opens, a.) the voltage across each branch will be 0V b.) The current in each branch will be zero c.) The current in each branch will increase to offset the decrease in total current d.) both "the voltage across each branch will be 0V" and "the current in each branch will be zero"

both "the voltage across each branch will be 0V" and "the current in each branch will be zero"

If one branch of a parallel circuit opens, the total current, IT, A.) doesn't change B.) decreases C.) increases d.) goes to zero

decreases

In a normally operating parallel circuit, the individual branch currents are a.) independent of each other b.) not affected by the value of the applied voltage c.) larger than the total current, IT, d.) none of the above

independent of each other

If one branch of a parallel circuit is short-circuited, a.) the fuse in the main line will blow b.) the voltage across the short-circuited branch will measure the full value of applied voltage c.) all the remaining branches are effectively short-circuited as well d.) both "the fuse in the main line will blow" and "all the remaining branches are effectively short-circuited as well"

both "the fuse in the main line will blow" and "all the remaining branches are effectively short-circuited as well"

When applying Kirchhoff's Current Law, a.) consider all currents flowing into a branch point positive and all currents directed away from that point negative b.) consider all currents flowing into a branch point negative and all currents directed away from that point positive c.) remember that the total of the currents entering a branch point must always be greater than the sum of the currents leaving that point d.) the algebraic sum of the currents entering and leaving a branch point does not necessarily have to be zero.

consider all currents flowing into a branch point positive and all currents directed away from that point negative

Kirchhoff's Voltage Law states that a.) the algebraic sum of the voltage sources and IR voltage drops in any closed path must total zero b.) the algebraic sum of the voltage sources and IR voltage drops around any closed path can never equal zero c.) the algebraic sum of all the currents flowing around any closed loop must equal zero d.) none of the above

the algebraic sum of the voltage sources and IR voltage drops in any closed path must total zero

A principal node is a.) a closed path or loop where the algebraic sum of the voltages must equal zero b.) the simplest possible closed path around a circuit c.) a junction where the branch currents can combine or divide d.) none of the above

a junction where the branch currents can combine or divide

The difference between a mesh current and a branch current is A. a mesh current is an assumed current and a branch current is an actual current B. the direction of the currents themselves C. a mesh current does not divide at a branch point D. both “a mesh current is an assumed current and a branch current is an actual current” and “a mesh current does not divide at a branch point”

both “a mesh current is an assumed current and a branch current is an actual current” and “a mesh current does not divide at a branch point”

Using the method of mesh currents, any resistance common to two meshes has a.) two opposing mesh currents b.) one common mesh current c.) zero current d.) none of the above

two opposing mesh currents

The fact that the sum of the resistor voltage drops equals the applied voltage in a series circuit is the basis for a.) Kirchhoff's Current Law b.) node-voltage analysis c.) Kirchhoff's Voltage Law d.) the method of mesh currents

Kirchhoff's Voltage Law

To apply the Superposition Theorem, all components must be a.) the active-type b.) both linear and bilateral c.) grounded d.) both nonlinear and unidirectional

both nonlinear and bilateral

When converting from a Norton-equivalent circuit to a Thevenin equivalent circuit or vice-versa, a.) RN and RTH have the same value b.) RN will always be larger than RTH c.) LN is short-circuited to find VTH d.) VTH is short-circuited to find IN

RN and RTH have the same value

When solving for the Thevenin equivalent resistance, RTH , a.) all voltage sources must be opened b.) all voltage sources must be short-circuited c.) all voltage sources must be converted to current sources d.) none of the above

all voltage sources must be short-circuited

With respect to terminals A and B in a complex network, the Thevenin voltage, VTH, is a.) the voltage across terminals A and B when they are short-circuited b.) the open-circuit voltage across terminals A and B c.) the same as the voltage applied to the complex network d.) none of the above

the open-circuit voltage across terminals A and B

With respect to terminals A and B in a complex network, the Norton current, IN, equals a.) the current flowing between terminals A and B when they are open b.) the total current supplied by the applied voltage to the network c.) zero when terminals A and B are short-circuited d.) the current flowing between terminals A and B when they are short-circuited

the current flowing between terminals A and B when they are short-circuited

In general, a capacitor is a component that can a.) pass a dc current b.) store an electric charge c.) act as a bar magnet d.) step up or step down an ac voltage

store an electric charge

How much charge in coulombs is stored by a 50uF capacitor with 20V across its plates? a.) Q= 100 Mc b.) Q= 2.5 uC c.) Q= 1 mC d.) Q= 1 uC

1 mC

A capacitance of 82,000 pF is the same as a.) 0.082 uF b.) 82 uF c.) 82 nF d.) both "0.082uF" and "82nF"

both "0.082uF" and "82nF"

A 47 uF capacitor has a stored charge of 2.35mC. What is the voltage across the capacitor plates? a.) 50 V b.) 110 Vapprox c.) 5 V d.) 100 V

50 V

One of the main applications of a capacitor is to a.) block ac and pass dc b.) block both dc and ac c.) block dc and pass ac d.) pass both dc and ac

block dc and pass ac

When checked with an ohmmeter, a shorted capacitor will measure a.) infinite ohms b.) zero ohms c.) somewhere in the range of 1 to 10 Megaohms d.) none of the above

zero ohms

A 0.33uF capacitor is in parallel with a 0.15uF and a 220,000pF capacitor. What is the total capacitance, CT? a.) 0.7 uF b.) 0.007Mf c.) 0.07uF d.) 7nF

0.7 uF

Which type of capacitor could explode if the polarity of voltage across its plates is incorrect? a.) air variable b.) mica c.) ceramic disk d.) aluminum electrolytic

aluminum electrolytic

A capacitor that can store 100uC of charge with 10V across its plates has a capacitance value of a.) 0.01 uF b.) 10 uF c.) 10nF d.) 100mF

10uF

The equivalent series resistance (ESR) of a capacitor should ideally be a.) infinite b.) as high as possible c.) around 100 kiloohms or so d.) zero

zero

The charge and discharge current of a capacitor flows a.) through the dielectric b.) to and from the capacitor plates c.) through the dielectric only until the capacitor is fully charged d.) straight through the dielectric from one plate to the other

to and from the capacitor plates

The capacitance of a capacitor is the ratio a.) charge to p.d. between plates b.) p.d. between plates to plate spacing c.) p.d. between plates to thickness of dielectric d.) p.d. between plates to charge

charge to potential difference between plates

State which of the following is false. The capacitance of a capacitor a.) is proportional to the cross-sectional area of the plates b.) is proportional to the distance between the plates c.) depends on the number of plates d.) is proportional to the relative permittivity of the dielectric

is proportional to the distance between the plates

Which of the following statement is false? a.) An air capacitor is normally a variable type b.) A paper capacitor generally has a shorter service life than most other types of capacitor c.) An electrolytic capacitor must be used only on a.c. supplies d.) Plastic capacitors generally operate satisfactorily under conditions of high temperature

An air capacitor is normally a variable type

The energy stored in a 10uF capacitor when charged to 500V is

1.25 J

The capacitance of a variable air capacitor is at maximum when a.) the movable plates half overlap the fixed plates b.) the movable plates are most widely separated from the fixed plates c.) both sets of plates are exactly meshed d.) the movable plates are closer to one side of the fixed plate than to the other

both sets of plates are exactly meshed

The unit of inductance is the a.) henry b.) farad c.) ohm d.) volt-ampere

henry

A transformer cannot be used to a.) step up or down an ac voltage b.) step up or down a dc voltage c.) match impedances d.) transfer power from primary to secondary

step up or down a dc voltage

The interaction between two inductors physically close together is called a.) counter emf b.) self inductance c.) mutual inductance d.) hysteresis

mutual inductance

If the secondary current in a step-down transformer increases, the primary current will a.) not change b.) increases c.) decreases d.) drop a little

increases

Inductance can be defined as the characteristic that a.) opposes a change in current b.) opposes a change in voltage c.) aids or enhances any change in current d.) stores electric charge

opposes a change in current

If the number of turns in a coil is doubled in the same length and area, the inductance, L, will a.) double b.) quadruple c.) stay the same d.) be cut in half

quadruple

An open coil has a.) zero resistance and zero inductance b.) infinite inductance and zero resistance c.) normal inductance but infinite resistance d.) infinite resistance and zero inductance

infinite resistance and zero inductance

Two 10H inductors are connected in series-aiding and have a mutual inductance, LM, of 0.75H. The total inductance, LT, of this combination

21.5H

How much is the self-induced voltage, VL, across a 100 mH inductor produced by a current change of 50,000 A/s? a.) 5kV b.) 50V c.) 5MV d.) 500kV

5kV

The measured voltage across an unloaded secondary of a transformer is usually a.) the same as the rated secondary voltage b.) 5 to 10% higher than the rated secondary voltage c.) 50% higher than the rated secondary voltage d.) 5 to 10% lower than the rated secondary voltage

5 to 10% higher than the rated secondary voltage

A laminated iron-core transformer has reduced eddy current losses because a.) the laminations are stacked vertically b.) more wire can be used with less dc resistance c.) the magnetic flux is in the air gap of the core d.) the laminations are insulated from each other

the laminations are insulated from each other

How much is the inductance of a coil that induces 50V when its current changes at the rate of 500 A/s? a.) 100 mH b.) 1 H c.) 100 uH d.) 10 uH

100 mH

A 100mH inductor is in parallel with a 150 mH and a 120 mH inductor. Assuming no mutual inductance between coils, how much us LEQ (equivalent inductance)? a.) 400 mH b.) 370 mH c.) 40 mH d.) 80 mH

40mH

A 400 uH coil is in series with a 1.2 mH coil without mutual inductance. How much is LT? a.) 401.2 uH b.) 300 uH c.) 160 uH d.) 1.6 mH

1.6 mH

How much is induced voltage, VL, across a 5H inductor carrying a steady dc current of 200 mA? a.) 0V b.) 1V c.) 100 kV d.) 120 Vac

For a coil, the dc resistance, ri, and inductance, L, are a.) in parallel b.) infinite c.) the same thing d.) in series

in series

An inductance of 0.08 uH is larger than a.) 0.0000008 H b.) 0.000000008 H c.) 0.000008 H d.) 0.00008 mH

0.0000000008 H

An ohmmeter is connected across an inductor and the pointer indicates zero ohms. The inductor is a.) good b.) open c.) shorted d.) partly shorted

shorted

75-79: In the notebook hay circuit siya.

75. 134 mA 76. 245 mA 77. 0.16 A 78. 6.4 V 79. 422 ohms

In a two-source circuit, one source acting alone produces 12 mA through a given branch. The other source acting alone produces 10 mA in the opposite direction through the same branch. The actual current through the branch is a.) 22 mA b.) 12 mA c.) 10 mA d.) 2 mA

2 mA