Ohm's Law / Power

(C)

B-005-002-009 Voltage drop means:

A the difference in voltage at output terminals of a transformer

B the voltage which is dissipated before useful work is accomplished

C the voltage developed across the terminals of a component

D any point in a radio circuit which has zero voltage

B-005-003-004 Which electrical circuit will have no current?

A A short circuit

B A complete circuit

C A closed circuit

D An open circuit

B-005-003-005 Which electrical circuit draws too much current?

A A dead circuit

B A closed circuit

C An open circuit

D A short circuit

B-005-004-001 If a current of 2 amperes flows through a 50-ohm resistor, what is the voltage across the resistor?

A 100 volts

B 48 volts

C 52 volts

D 25 volts

B-005-004-002 How is the current in a DC circuit calculated when the voltage and resistance are known?

A Current equals voltage divided by resistance

B Current equals resistance multiplied by voltage

C Current equals resistance divided by voltage

D Current equals power divided by voltage

B-005-004-003 How is the resistance in a DC circuit calculated when the voltage and current are known?

A Resistance equals current divided by voltage

B Resistance equals voltage divided by current

C Resistance equals current multiplied by voltage

D Resistance equals power divided by voltage

B-005-004-004 How is the voltage in a DC circuit calculated when the current and resistance are known?

A Voltage equals current multiplied by resistance

B Voltage equals current divided by resistance

C Voltage equals resistance divided by current

D Voltage equals power divided by current

B-005-004-005 If a 12-volt battery supplies 0.25 ampere to a circuit, what is the circuit's resistance?

A 0.25 ohm

B 48 ohms

C 3 ohms

D 12 ohms

B-005-004-006 Calculate the value of resistance necessary to drop 100 volts with current flow of 0.8 milliamperes:

A 1250 ohms

B 1.25 kilohms

C 125 kilohms

D 125 ohms

B-005-004-007 The voltage required to force a current of 4.4 amperes through a resistance of 50 ohms is:

A 22.0 volts

B 0.220 volt

C 220 volts

D 2220 volts

B-005-004-008 A lamp has a resistance of 30 ohms and a 6 volt battery is connected. The current flow will be:

A 0.5 ampere

B 0.005 ampere

C 0.2 ampere

D 2 amperes

B-005-004-009 What voltage would be needed to supply a current of 200 milliamperes, to operate an electric lamp which has a resistance of 25 ohms?

A 225 volts

B 5 volts

C 8 volts

D 175 volts

B-005-004-010 The resistance of a circuit can be found by using one of the following:

A R = E x I

B R = E/I

C R = I/E

D R = E/R

B-005-004-011 If a 3 volt battery supplies 300 milliamperes to a circuit, the circuit resistance is:

A 5 ohms

B 3 ohms

C 10 ohms

D 9 ohms

B-005-005-001 In a parallel circuit with a voltage source and several branch resistors, how is the total current related to the current in the branch resistors?

A It equals the average of the branch current through each resistor

B It decreases as more parallel resistors are added to the circuit

C It is the sum of each resistor's voltage drop multiplied by the total number of resistors

D It equals the sum of the branch current through each resistor

(C)

B-005-005-002 Three resistors, respectively rated at 10, 15 and 20 ohms are connected in parallel across a 6-volt battery. Which statement is true?

A The voltage drop across each resistance added together equals 6 volts

B The voltage drop across the 20 ohm resistance is greater than the voltage across the 10 ohm resistance

C The current through the 10 ohms, 15 ohms and 20 ohms separate resistances, when added together, equals the total current drawn from the battery

D The current flowing through the 10 ohm resistance is less than that flowing through the 20 ohm resistance

B-005-005-003 Total resistance in a parallel circuit:

A depends upon the applied voltage

B is always less than the smallest resistance

C depends upon the voltage drop across each branch

D could be equal to the resistance of one branch

B-005-005-004 Two resistors are connected in parallel and are connected across a 40 volt battery. If each resistor is 1000 ohms, the total current is:

A 80 milliamperes

B 40 milliamperes

C 80 amperes

D 40 amperes

B-005-005-005 The total resistance of resistors connected in series is:

A equal to the lowest resistance present

B greater than the resistance of any one resistor

C less than the resistance of any one resistor

D equal to the highest resistance present

B-005-005-006 Five 10 ohm resistors connected in series equals:

A 5 ohms

B 10 ohms

C 1 ohm

D 50 ohms

A Five 100 ohm

B Five 24 ohm

C Six 22 ohm

D Two 62 ohm

B-005-005-008 If ten resistors of equal value were wired in parallel, the total resistance would be:

A 10 + R

B R / 10

C 10 / R

D 10 x R

B-005-005-009 The total resistance of four 68 ohm resistors wired in parallel is:

A 272 ohms

B 17 ohms

C 12 ohms

D 34 ohms

B-005-005-010 Two resistors are in parallel. Resistor A carries twice the current of resistor B, which means that:

A the voltage across A is twice that across B

B B has half the resistance of A

C A has half the resistance of B

D the voltage across B is twice that across A

B-005-005-011 The total current in a parallel circuit is equal to the:

A current in any one of the parallel branches

B sum of the currents through all the parallel branches

C source voltage divided by the value of one of the resistive elements

D source voltage divided by the sum of the resistive elements

(B)

B-005-006-001 Why would a large size resistor be used instead of a smaller one of the same resistance?

A For less impedance in the circuit

B For greater power dissipation

C For better response time

D For a higher current gain

B-005-006-002 How many watts of electrical power are used by a 12 volt DC light bulb that draws 0.2 ampere?

A 6 watts

B 2.4 watts

C 60 watts

D 24 watts

B-005-006-003 The DC input power of a transmitter operating at 12 volts and drawing 500 milliamperes would be:

A 6 watts

B 20 watts

C 500 watts

D 12 watts

B-005-006-004 When two 500 ohm 1 watt resistors are connected in series, the maximum total power that can be dissipated by the resistors is:

A 2 watts

B 1 watt

C 1/2 watt

D 4 watts

B-005-006-005 When two 500 ohm 1 watt resistors are connected in parallel, they can dissipate a maximum total power of:

A 1/2 watt

B 1 watt

C 4 watts

D 2 watts

A Increase four times

B Decrease to half

C Double

D No change

B-005-006-007 Which combination of resistors could make up a 50 ohms dummy load capable of safely dissipating 5 watts?

A Two 5-watt 100 ohms resistors in series

B Two 2-watt 25 ohms resistors in series

C Ten quarter-watt 500 ohms resistors in parallel

D Four 2-watt 200 ohms resistors in parallel

B-005-006-008 A 12 volt light bulb is rated at a power of 30 watts. The current drawn would be:

A 30/12 amperes

B 18 amperes

C 360 amperes

D 12/30 amperes

B-005-006-009 If two 10 ohm resistors are connected in series with a 10 volt battery, the power consumption would be:

A 5 watts

B 10 watts

C 20 watts

D 100 watts

B-005-006-010 One advantage of replacing a 50 ohm resistor with a parallel combination of two similarly rated 100 ohm resistors is that the parallel combination will have:

A greater resistance and similar power rating

B lesser resistance and similar power rating

C the same resistance but greater power rating

D the same resistance but lesser power rating

B-005-006-011 Resistor wattage ratings are:

A calculated according to physical size and tolerance rating

B expressed in joules

C variable in steps of one hundred

D determined by heat dissipation qualities

(B)

B-005-003-001 What is the word used to describe the rate at which electrical energy is used?

A Resistance

B Power

C Current

D Voltage

B-005-003-002 If you have light bulbs marked 40 watts, 60 watts and 100 watts, which one will use electrical energy the fastest?

A The 40 watt bulb

B The 60 watt bulb

C The 100 watt bulb

D They will all be the same

B-005-003-003 What is the basic unit of electrical power?

A The watt

B The ampere

C The volt

D The ohm

B-005-003-006 Power is expressed in:

A watts

B volts

C amperes

D ohms

B-005-003-007 Which of the following two quantities should be multiplied together to find power?

A Voltage and current

B Inductance and capacitance

C Voltage and inductance

D Resistance and capacitance

B-005-003-008 Which two electrical units multiplied together give the unit "watts"?

A Volts and amperes

B Volts and farads

C Farads and henrys

D Amperes and henrys

B-005-003-009 A resistor in a circuit becomes very hot and starts to burn. This is because the resistor is dissipating too much:

A power

B voltage

C resistance

D current

High power resistors are usually large with heavy leads. The size aids the operation of the resistor by:

A making it shock proof

B allowing heat to dissipate more readily

C allowing higher voltage to be handled

D increasing the effective resistance of the resistor

B-005-003-011 The resistor that could dissipate the most heat would be marked:

A 100 ohms

B 2 ohms

C 0.5 watt

D 20 watts

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