Question 13028 of 749 · Maryland Journeyperson Electrician Exam
Resistors of 5, 10 and 15 ohms are connected in series across 120 volts. What is the voltage across the 10 ohm resistor?
Exactly one answer is correct.
You got of questions right. Here on the question pages nobody remembers which ones you got wrong. The trainer saves your progress and asks the mistakes again until they stick.
Or free: the 10 questions most people get wrong
Show solution
Correct answer to question 13028
- D: 40 V
Explanation
Total resistance is 30 ohms, so I = 120 / 30 = 4 A, and the drop across 10 ohms is 4 x 10 = 40 V. In a series circuit the source voltage divides in proportion to resistance; 120 V would only appear across a parallel branch.
More questions: Electrical Calculations
- 13031A 120 volt single-phase branch circuit uses 12 AWG copper (6,530 circular mils), runs 100 feet one way and carries 16 A. Using K = 12.9, what is the voltage drop?
- 13032A 240 volt single-phase circuit of 10 AWG copper (10,380 circular mils) supplies 24 A at 150 feet one way. What is the voltage drop as a percentage of the supply voltage?
- 13033A three-phase 480 volt load draws 50 A over 6 AWG copper conductors (26,240 circular mils), 200 feet one way. What is the line-to-line voltage drop?
- 13034A 240 volt single-phase feeder uses 4 AWG aluminum conductors (41,740 circular mils), 175 feet one way, carrying 60 A. Using K = 21.2 for aluminum, what is the voltage drop?
- 13035A 240 volt single-phase load of 40 A is located 180 feet from the panel. What is the smallest copper conductor that keeps voltage drop at or below 3 %?
- 13036A three-phase 208 volt load of 90 A is 150 feet from the source. Ignoring ampacity, what is the smallest copper conductor that limits voltage drop to 3 %?