A 12 volt supply is across a 480 ohm resistor. What is the current in milliamperes?Own question; the answer is worked out again from the numbers in it. Ohm's law as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), pages 3-5 to 3-9.
A 15 ohm heating element must carry 16 amperes. What voltage is needed?Own question; the answer is worked out again from the numbers in it. Ohm's law as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), pages 3-5 to 3-9.
A 24 volt control circuit draws 2 amperes. What is the resistance of the load?Own question; the answer is worked out again from the numbers in it. Ohm's law as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), pages 3-5 to 3-9.
A 40 ohm heating element draws 3 amperes. How many volts does Ohm's law put across the element?Own question; the answer is worked out again from the numbers in it. Ohm's law as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), pages 3-5 to 3-9.
Show all 80 questions (76 more)
Ohm's law, continued
A 120 volt circuit draws 10 amperes. If the resistance doubles and the voltage stays the same, what is the new current?Own question; the answer is worked out again from the numbers in it. Ohm's law as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), pages 3-5 to 3-9.
A 120 volt circuit feeds a heater with 24 ohms of resistance. How much current flows?Own question; the answer is worked out again from the numbers in it. Ohm's law as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), pages 3-5 to 3-9.
A 240 volt water heater element measures 12 ohms. What current does it draw?Own question; the answer is worked out again from the numbers in it. Ohm's law as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), pages 3-5 to 3-9.
A fixed resistance draws 4 amperes at 120 volts. What does it draw at 240 volts?Own question; the answer is worked out again from the numbers in it. Ohm's law as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), pages 3-5 to 3-9.
A lamp draws 0.5 ampere on a 120 volt circuit. What is its resistance while lit?Own question; the answer is worked out again from the numbers in it. Ohm's law as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), pages 3-5 to 3-9.
A relay coil of 600 ohms carries 0.02 ampere. What voltage is across the coil?Own question; the answer is worked out again from the numbers in it. Ohm's law as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), pages 3-5 to 3-9.
Power and energy 10
A 100 watt lamp burns for 50 hours. At 12 cents per kilowatt-hour, what does that energy cost?Own question; the answer is worked out again from the numbers in it. Power formulas as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), pages 3-12 to 3-15; the kilowatt-hour, efficiency and 746 watts to the horsepower on page 3-18.
A 120 volt circuit carries 12.5 amperes. How much power does the load use?Own question; the answer is worked out again from the numbers in it. Power formulas as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), pages 3-12 to 3-15; the kilowatt-hour, efficiency and 746 watts to the horsepower on page 3-18.
A 240 volt heater has an element of 28.8 ohms. What is its power?Own question; the answer is worked out again from the numbers in it. Power formulas as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), pages 3-12 to 3-15; the kilowatt-hour, efficiency and 746 watts to the horsepower on page 3-18.
A 1,500 watt heater runs for 6 hours. How many kilowatt-hours does it use?Own question; the answer is worked out again from the numbers in it. Power formulas as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), pages 3-12 to 3-15; the kilowatt-hour, efficiency and 746 watts to the horsepower on page 3-18.
A 1,800 watt hair dryer runs on 120 volts. What current does it draw?Own question; the answer is worked out again from the numbers in it. Power formulas as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), pages 3-12 to 3-15; the kilowatt-hour, efficiency and 746 watts to the horsepower on page 3-18.
A current of 5 amperes flows through a 20 ohm resistor. How much power is turned to heat?Own question; the answer is worked out again from the numbers in it. Power formulas as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), pages 3-12 to 3-15; the kilowatt-hour, efficiency and 746 watts to the horsepower on page 3-18.
A motor takes 2,000 watts from the line and delivers 1,700 watts at the shaft. What is its efficiency?Own question; the answer is worked out again from the numbers in it. Power formulas as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), pages 3-12 to 3-15; the kilowatt-hour, efficiency and 746 watts to the horsepower on page 3-18.
One horsepower equals 746 watts. A 2 horsepower motor is 80 percent efficient. How much power does it take from the line at full load?Own question; the answer is worked out again from the numbers in it. Power formulas as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), pages 3-12 to 3-15; the kilowatt-hour, efficiency and 746 watts to the horsepower on page 3-18.
One horsepower equals 746 watts. A motor delivers 1,492 watts at its shaft. How many horsepower is that?Own question; the answer is worked out again from the numbers in it. Power formulas as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), pages 3-12 to 3-15; the kilowatt-hour, efficiency and 746 watts to the horsepower on page 3-18.
One horsepower equals 746 watts. How many watts is a 5 horsepower motor rated to deliver?Own question; the answer is worked out again from the numbers in it. Power formulas as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), pages 3-12 to 3-15; the kilowatt-hour, efficiency and 746 watts to the horsepower on page 3-18.
Series and parallel resistance 10
A 12 ohm load and a 4 ohm load are in parallel. What is their combined resistance?Own question; the answer is worked out again from the numbers in it. Series rules as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), page 3-28; parallel rules on pages 3-49 to 3-64.
A 30 ohm load and a 60 ohm load sit in parallel branches of one circuit. What is their combined resistance?Own question; the answer is worked out again from the numbers in it. Series rules as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), page 3-28; parallel rules on pages 3-49 to 3-64.
A 120 volt circuit has a 40 ohm branch and a 60 ohm branch in parallel. What is the total current?Own question; the answer is worked out again from the numbers in it. Series rules as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), page 3-28; parallel rules on pages 3-49 to 3-64.
Four 60 ohm heating elements are wired in parallel. What is their combined resistance?Own question; the answer is worked out again from the numbers in it. Series rules as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), page 3-28; parallel rules on pages 3-49 to 3-64.
Resistors of 10, 22 and 47 ohms are connected in series. What is the total resistance?Own question; the answer is worked out again from the numbers in it. Series rules as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), page 3-28; parallel rules on pages 3-49 to 3-64.
Resistors of 20 and 40 ohms are in series across 120 volts. What current flows?Own question; the answer is worked out again from the numbers in it. Series rules as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), page 3-28; parallel rules on pages 3-49 to 3-64.
Resistors of 20, 30 and 60 ohms are in parallel. What is the total resistance?Own question; the answer is worked out again from the numbers in it. Series rules as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), page 3-28; parallel rules on pages 3-49 to 3-64.
Resistors of 30 and 90 ohms are in series across 240 volts. What voltage is across the 90 ohm resistor?Own question; the answer is worked out again from the numbers in it. Series rules as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), page 3-28; parallel rules on pages 3-49 to 3-64.
Two 20 ohm resistors in parallel feed a 10 ohm resistor in series. What is the resistance of the whole circuit?Own question; the answer is worked out again from the numbers in it. Series rules as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), page 3-28; parallel rules on pages 3-49 to 3-64.
Two 100 ohm lamps are wired in parallel across one source. What is their combined resistance?Own question; the answer is worked out again from the numbers in it. Series rules as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), page 3-28; parallel rules on pages 3-49 to 3-64.
Voltage drop 10
A 120 volt circuit loses 3.6 volts in the wire. What is the percent voltage drop?Own question; the answer is worked out again from the numbers in it. Voltage drop is Ohm's law applied to the wire, as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), pages 3-5 to 3-9. The wire's resistance is given in the question.
A 120 volt source feeds a load through wire that drops 3.6 volts. What voltage reaches the load?Own question; the answer is worked out again from the numbers in it. Voltage drop is Ohm's law applied to the wire, as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), pages 3-5 to 3-9. The wire's resistance is given in the question.
A 240 volt circuit loses 6 volts in its conductors. What percent voltage drop is that?Own question; the answer is worked out again from the numbers in it. Voltage drop is Ohm's law applied to the wire, as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), pages 3-5 to 3-9. The wire's resistance is given in the question.
A circuit carries 16 amperes, and the wire is to lose no more than 4 volts. What is the most resistance the conductors can have?Own question; the answer is worked out again from the numbers in it. Voltage drop is Ohm's law applied to the wire, as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), pages 3-5 to 3-9. The wire's resistance is given in the question.
A designer allows a 2 percent voltage drop on a 480 volt feeder. How many volts is that?Own question; the answer is worked out again from the numbers in it. Voltage drop is Ohm's law applied to the wire, as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), pages 3-5 to 3-9. The wire's resistance is given in the question.
A feeder's conductors have a total resistance of 0.25 ohm and carry 40 amperes. What is the voltage drop?Own question; the answer is worked out again from the numbers in it. Voltage drop is Ohm's law applied to the wire, as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), pages 3-5 to 3-9. The wire's resistance is given in the question.
A wire has a resistance of 1.2 ohms per 1,000 feet. What is the resistance of 250 feet of it?Own question; the answer is worked out again from the numbers in it. Voltage drop is Ohm's law applied to the wire, as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), pages 3-5 to 3-9. The wire's resistance is given in the question.
A wire has a resistance of 2 ohms per 1,000 feet. A load 150 feet from the panel is fed out and back by that wire and draws 10 amperes. What is the voltage drop?Own question; the answer is worked out again from the numbers in it. Voltage drop is Ohm's law applied to the wire, as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), pages 3-5 to 3-9. The wire's resistance is given in the question.
Conductors with 0.5 ohm of total resistance carry 20 amperes. How much power is lost as heat in the conductors?Own question; the answer is worked out again from the numbers in it. Voltage drop is Ohm's law applied to the wire, as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), pages 3-5 to 3-9. The wire's resistance is given in the question.
The wires of a branch circuit have 0.3 ohm of resistance in all. At 15 amperes, how many volts are lost in the wire?Own question; the answer is worked out again from the numbers in it. Voltage drop is Ohm's law applied to the wire, as printed in Navy Electricity and Electronics Training Series, Module 1 (NAVEDTRA 14173, September 1998), pages 3-5 to 3-9. The wire's resistance is given in the question.
Transformer ratios 10
A 12 kilovolt-ampere single-phase transformer has a 240 volt secondary. What is the full-load secondary current?Own question; the answer is worked out again from the numbers in it. Turns, voltage and current ratios and the power relationship as printed in Navy Electricity and Electronics Training Series, Module 2 (NAVEDTRA 14174, September 1998), pages 5-11 to 5-17.
A control transformer steps 240 volts down to 24 volts. Its primary has 500 turns. How many turns are on the secondary?Own question; the answer is worked out again from the numbers in it. Turns, voltage and current ratios and the power relationship as printed in Navy Electricity and Electronics Training Series, Module 2 (NAVEDTRA 14174, September 1998), pages 5-11 to 5-17.
A single-phase transformer secondary supplies 25 amperes at 240 volts. What is that load in kilovolt-amperes?Own question; the answer is worked out again from the numbers in it. Turns, voltage and current ratios and the power relationship as printed in Navy Electricity and Electronics Training Series, Module 2 (NAVEDTRA 14174, September 1998), pages 5-11 to 5-17.
A transformer has 150 primary turns and 600 secondary turns. With 120 volts applied to the primary, what voltage appears on the secondary?Own question; the answer is worked out again from the numbers in it. Turns, voltage and current ratios and the power relationship as printed in Navy Electricity and Electronics Training Series, Module 2 (NAVEDTRA 14174, September 1998), pages 5-11 to 5-17.
A transformer has 800 turns on the primary and 200 turns on the secondary. With 480 volts on the primary, what is the secondary voltage?Own question; the answer is worked out again from the numbers in it. Turns, voltage and current ratios and the power relationship as printed in Navy Electricity and Electronics Training Series, Module 2 (NAVEDTRA 14174, September 1998), pages 5-11 to 5-17.
A transformer steps 2,400 volts down to 240 volts. What is its turns ratio, primary to secondary?Own question; the answer is worked out again from the numbers in it. Turns, voltage and current ratios and the power relationship as printed in Navy Electricity and Electronics Training Series, Module 2 (NAVEDTRA 14174, September 1998), pages 5-11 to 5-17.
A transformer with a 20 to 1 step-down turns ratio delivers 12 volts on the secondary. What is the primary voltage?Own question; the answer is worked out again from the numbers in it. Turns, voltage and current ratios and the power relationship as printed in Navy Electricity and Electronics Training Series, Module 2 (NAVEDTRA 14174, September 1998), pages 5-11 to 5-17.
An ideal transformer delivers 1,200 watts to a resistive load. Its primary is connected to 240 volts. With losses ignored, what is the primary current?Own question; the answer is worked out again from the numbers in it. Turns, voltage and current ratios and the power relationship as printed in Navy Electricity and Electronics Training Series, Module 2 (NAVEDTRA 14174, September 1998), pages 5-11 to 5-17.
An ideal transformer steps 480 volts down to 120 volts. The secondary delivers 40 amperes. What is the primary current?Own question; the answer is worked out again from the numbers in it. Turns, voltage and current ratios and the power relationship as printed in Navy Electricity and Electronics Training Series, Module 2 (NAVEDTRA 14174, September 1998), pages 5-11 to 5-17.
An ideal transformer with a 4 to 1 step-down turns ratio draws 5 amperes on the primary. What is the secondary current?Own question; the answer is worked out again from the numbers in it. Turns, voltage and current ratios and the power relationship as printed in Navy Electricity and Electronics Training Series, Module 2 (NAVEDTRA 14174, September 1998), pages 5-11 to 5-17.
Three-phase and power factor 10
A load takes 15 kilovolt-amperes at a power factor of 0.9. What is the true power in kilowatts?Own question; the answer is worked out again from its numbers. Line and phase values (1.73) as printed in Navy Electricity and Electronics Training Series, Module 5 (NAVEDTRA 14177, September 1998), page 3-11; power factor in Module 2 of the series (NAVEDTRA 14174, September 1998), page 4-23.
A load takes 8,000 watts of true power and 10,000 volt-amperes of apparent power. What is its power factor?Own question; the answer is worked out again from its numbers. Line and phase values (1.73) as printed in Navy Electricity and Electronics Training Series, Module 5 (NAVEDTRA 14177, September 1998), page 3-11; power factor in Module 2 of the series (NAVEDTRA 14174, September 1998), page 4-23.
For a three-phase load, volt-amperes = 1.73 x line volts x line amperes. What is the apparent power, in kilovolt-amperes, of a load drawing 50 amperes at 480 volts?Own question; the answer is worked out again from its numbers. Line and phase values (1.73) as printed in Navy Electricity and Electronics Training Series, Module 5 (NAVEDTRA 14177, September 1998), page 3-11; power factor in Module 2 of the series (NAVEDTRA 14174, September 1998), page 4-23.
For a three-phase load, volt-amperes = 1.73 x line volts x line amperes. What is the full-load line current of a 51.9 kilovolt-ampere transformer at 480 volts?Own question; the answer is worked out again from its numbers. Line and phase values (1.73) as printed in Navy Electricity and Electronics Training Series, Module 5 (NAVEDTRA 14177, September 1998), page 3-11; power factor in Module 2 of the series (NAVEDTRA 14174, September 1998), page 4-23.
For a three-phase load, volt-amperes = 1.73 x line volts x line amperes. What is the line current of a 17.3 kilovolt-ampere load at 200 volts?Own question; the answer is worked out again from its numbers. Line and phase values (1.73) as printed in Navy Electricity and Electronics Training Series, Module 5 (NAVEDTRA 14177, September 1998), page 3-11; power factor in Module 2 of the series (NAVEDTRA 14174, September 1998), page 4-23.
For a three-phase load, watts = 1.73 x line volts x line amperes x power factor. What power does a load take at 480 volts and 20 amperes with a power factor of 1?Own question; the answer is worked out again from its numbers. Line and phase values (1.73) as printed in Navy Electricity and Electronics Training Series, Module 5 (NAVEDTRA 14177, September 1998), page 3-11; power factor in Module 2 of the series (NAVEDTRA 14174, September 1998), page 4-23.
For a three-phase load, watts = 1.73 x line volts x line amperes x power factor. What power does a motor take at 240 volts and 25 amperes with a power factor of 0.8?Own question; the answer is worked out again from its numbers. Line and phase values (1.73) as printed in Navy Electricity and Electronics Training Series, Module 5 (NAVEDTRA 14177, September 1998), page 3-11; power factor in Module 2 of the series (NAVEDTRA 14174, September 1998), page 4-23.
In a delta connection each line current is 1.73 times the phase current. Each phase carries 30 amperes. What is the line current?Own question; the answer is worked out again from its numbers. Line and phase values (1.73) as printed in Navy Electricity and Electronics Training Series, Module 5 (NAVEDTRA 14177, September 1998), page 3-11; power factor in Module 2 of the series (NAVEDTRA 14174, September 1998), page 4-23.
In a wye-connected system each line voltage is 1.73 times the phase voltage. The line voltage is 480 volts. What is the phase voltage, to the nearest volt?Own question; the answer is worked out again from its numbers. Line and phase values (1.73) as printed in Navy Electricity and Electronics Training Series, Module 5 (NAVEDTRA 14177, September 1998), page 3-11; power factor in Module 2 of the series (NAVEDTRA 14174, September 1998), page 4-23.
In a wye-connected system each line voltage is 1.73 times the phase voltage. The phase voltage is 120 volts. What is the line voltage?Own question; the answer is worked out again from its numbers. Line and phase values (1.73) as printed in Navy Electricity and Electronics Training Series, Module 5 (NAVEDTRA 14177, September 1998), page 3-11; power factor in Module 2 of the series (NAVEDTRA 14174, September 1998), page 4-23.
Percentages and load sums 10
A 100 ampere panel carries 62.5 amperes. How many more amperes can be added before it reaches its rating?Own question; the answer is worked out again from the numbers in it. The percentage or factor is given in the question and is not taken from any code.
A 120 volt circuit feeds 12 lamps of 60 watts each. What current do the lamps draw together?Own question; the answer is worked out again from the numbers in it. The percentage or factor is given in the question and is not taken from any code.
A circuit rated 20 amperes carries 13 amperes. What percent of its rating is in use?Own question; the answer is worked out again from the numbers in it. The percentage or factor is given in the question and is not taken from any code.
A circuit serves loads of 1,200, 600 and 360 watts. What is the total load?Own question; the answer is worked out again from the numbers in it. The percentage or factor is given in the question and is not taken from any code.
A designer allows 3.5 volt-amperes of lighting load per square foot for an office of 2,000 square feet. What lighting load is that?Own question; the answer is worked out again from the numbers in it. The percentage or factor is given in the question and is not taken from any code.
A fuse is rated 60 amperes. How many amperes is a load equal to 75 percent of that rating?Own question; the answer is worked out again from the numbers in it. The percentage or factor is given in the question and is not taken from any code.
A load grows from 40 amperes to 50 amperes. What is the percent increase?Own question; the answer is worked out again from the numbers in it. The percentage or factor is given in the question and is not taken from any code.
A motor draws 16 amperes at full load. What is 150 percent of that current?Own question; the answer is worked out again from the numbers in it. The percentage or factor is given in the question and is not taken from any code.
A panel has 40,000 volt-amperes of connected load. The designer applies a demand factor of 60 percent. What is the demand load?Own question; the answer is worked out again from the numbers in it. The percentage or factor is given in the question and is not taken from any code.
Branch loads of 7.5, 4.2 and 3.3 amperes are on at the same time. What is the total current?Own question; the answer is worked out again from the numbers in it. The percentage or factor is given in the question and is not taken from any code.
Fractions and conduit bends 10
A 10 foot length of conduit has a piece 3 5/8 feet long cut from it. With the width of the cut ignored, how much is left?Own question; the answer is worked out again from the numbers in it. The multiplier, take-up or shrink figure is given in the question.
A 90 degree stub is to rise 12 inches. The bender's take-up, given for this question, is 5 inches. How far from the end of the conduit does the mark go?Own question; the answer is worked out again from the numbers in it. The multiplier, take-up or shrink figure is given in the question.
An offset of 4 inches is made with 10 degree bends, for which the multiplier is 6. What is the distance between the bend marks?Own question; the answer is worked out again from the numbers in it. The multiplier, take-up or shrink figure is given in the question.
An offset of 5 inches is made with 22.5 degree bends, for which the multiplier is 2.6. What is the distance between the bend marks?Own question; the answer is worked out again from the numbers in it. The multiplier, take-up or shrink figure is given in the question.
An offset of 6 inches is made with 30 degree bends, for which the multiplier is 2. How far apart are the bend marks?Own question; the answer is worked out again from the numbers in it. The multiplier, take-up or shrink figure is given in the question.
An offset of 8 inches is made with 30 degree bends. For this question the run shortens by 1/4 inch for each inch of offset. How much does the run shorten?Own question; the answer is worked out again from the numbers in it. The multiplier, take-up or shrink figure is given in the question.
An offset of 10 inches is made with 45 degree bends, for which the multiplier is 1.4. What is the distance between the bend marks?Own question; the answer is worked out again from the numbers in it. The multiplier, take-up or shrink figure is given in the question.
Bend marks are 18 inches apart and the bends are 30 degrees, for which the multiplier is 2. What offset does that make?Own question; the answer is worked out again from the numbers in it. The multiplier, take-up or shrink figure is given in the question.
Conduit pieces of 3 1/2 feet and 2 3/4 feet are coupled end to end. What is the total length?Own question; the answer is worked out again from the numbers in it. The multiplier, take-up or shrink figure is given in the question.
How many whole pieces 1 1/2 feet long can be cut from a 10 foot length of conduit, with the width of each cut ignored?Own question; the answer is worked out again from the numbers in it. The multiplier, take-up or shrink figure is given in the question.
How this list was compiled: Our own arithmetic questions. Every voltage, current, resistance, length, price and load is made up for the drill, and none is a real statistic or a value from a table or a code. The answer to each is arithmetic on the numbers in the question, worked out when the bank was written and again from the numbers read back out of the question text (2026-10-04). The formulas are the ones printed in the Navy Electricity and Electronics Training Series, a public training text of the United States Navy approved for public release: Module 1, Introduction to Matter, Energy, and Direct Current (NAVEDTRA 14173, September 1998), Module 2, Introduction to Alternating Current and Transformers (NAVEDTRA 14174, September 1998) and Module 5, Introduction to Generators and Motors (NAVEDTRA 14177, September 1998), each read 2026-10-04 in the copy at https://archive.org/details/NEETSModule01 , https://archive.org/details/NEETSModule02 and https://archive.org/details/NEETSModule05 . Licence: Questions, choices and explanations are original work of this site. The training series is a work of the United States Navy, approved for public release, and no question or example is copied from it.
How it works
This electrician practice math test is circuit arithmetic of our own: Ohm's law, power, series and parallel resistance, voltage drop, transformers, three-phase power, load sums and conduit bends. Every number needed is in the question, and every answer shows its working.
Read the full guide
What is left out
No value from an electrical code, an ampacity table or a wire table is used, and no board's, school's or employer's test is copied, so no pass mark is implied.
Eight topics in this electrician math test
The Start from menu under the question sets one: Ohm's law, power and energy, series and parallel resistance, voltage drop, transformer ratios, three-phase and power factor, percentages and load sums, or fractions and conduit bends. Every circuit, motor, panel and conduit run is made up.
Print and exam mode
Print, on the score card, makes a question sheet, and a tick adds an answer key. Exam mode draws 25 questions; that length is this site's choice.
Each question gives the wire's resistance, the bend multiplier or the horsepower conversion it needs, so use the figure given.
Kilovolt-amperes times 1,000 gives volt-amperes: convert before you divide by volts.
The Missed pile under More options keeps what you got wrong until you answer it right.
Questions and answers
What math is on an electrician math test?
Whoever sets it decides: a licensing board, an apprenticeship program or an employer writes its own. This page copies none of them. It drills eight kinds of circuit arithmetic, from Ohm's law to the distance between conduit bends.
How do you work out voltage drop?
Multiply the current by the resistance of the wire. A run with 0.25 ohm of total resistance carrying 40 amperes drops 40 x 0.25 = 10 volts. Each question here gives the wire's resistance, so no table is needed.
How do you find the secondary voltage of a transformer?
Multiply the primary voltage by the secondary turns and divide by the primary turns. With 800 primary turns, 200 secondary turns and 480 volts on the primary, the secondary is 480 x 200 / 800 = 120 volts.
How many watts are in one horsepower?
746 watts, as the Navy's electricity training series prints it. A 5 horsepower motor is rated to deliver 5 x 746 = 3,730 watts. Each horsepower question here states that conversion.
Is this from a real licensing exam?
No. It is unofficial practice written for this site. No question comes from a real exam, a test publisher or a prep book, and no code book value is used. Exam mode's 25 questions are this site's choice.