2. If the total combined resistance of R2 and R3 is 10 ohms, what is the total resistance of the entire circuit in figure?

3. Assuming the battery in the figure is 30 volts, what is the total current in the circuit?

4. According to Kirchhoff’s voltage law, which of the following Ohm’s law equations may be used to find the voltage drop across a resistor?

5. A 120-volt circuit has an electric heater connected with a current rating of 7.5 amperes. What is the resistance in ohms of the connected pure resistance load?

What current is drawn by a 277-volt fluorescent lamp with 8 ohms resistance?

7. If the impedance Z of the circuit impedance triangle in the figure

is 5 ohms and angle A is 30°, what is the value of the inductive reactance (XL)?

8. What is the minimum general lighting load permitted by the NEC in a 4500 square foot warehouse?

9. What is the minimum general lighting load permitted in a 1500 square foot single-family dwelling as specified in Table 220.12 of the NEC?

10. The voltage per turn for a transformer is 1.25 volts. What is the voltage of the transformer if it has 192 turns?

11. A 50 kVA, three-phase, delta-to-wye connected, 480/120-208 volt transformer is used to supply a lighting load. What is the rated phase current on the primary side?

12. A 50 kVA, three-phase, delta-to-wye connected 480/120-208 volt transformer used to supply a balanced lighting load will have what line-current rating on the secondary?

13. A 480/277 volt, Y-connected transformer is used to supply a balanced 277-volt, single-phase lighting load of 40,000 watts. What size transformer (kVA) should be used?

14. What is the maximum allowable wattage that can be connected to a 240-volt, 20-ampere, single-phase circuit feeding residential electric heaters?

15. An electric oven is rated at 2000 watts when connected to a 460-volt circuit. What is the resistance of the heating element?

16. The minimum allowable number of 120-volt, 15-ampere, 2-wire lighting branch circuits required for a residence 70 feet by 30 feet are:

17. A voltage drop of 3 volts has been determined on a 120-volt circuit. What percent is the voltage drop?

18. If a 120-volt circuit feeds six 80-watt fluorescent lamps, what current is drawn if the power factor is 0.91?

19. Calculate the minimum volt-ampere capacity of a 155,000 square foot school.

20. A store building 50 feet x 60 feet uses fluorescent lighting fixtures to illuminate the interior. If each fixture is to illuminate 60 square feet, how many light fixtures will have to be installed?

21. An electric heating element has an energized resistance of 30 ohms and is connected to a 120-volt circuit. How much current will flow in the circuit?

22. An electric heating element has an energized resistance of 30 ohms and is connected to a 120-volt circuit. How many watts of heat are being produced by the heating element?

23. A 240-volt air-conditioning compressor has an apparent resistance of 8 ohms. How much current will flow in the circuit?

24. A 240-volt air-conditioning compressor has an apparent resistance of 8 ohms. How many watts of power are being used?

25. A 3600-watt motor is connected to a 240-volt single-phase, 2-wire circuit. What is the minimum size THW conductor allowed to carry the load?

26. A clamp-on ammeter has three turns of wire wrapped around the movable jaw. If the meter is indicating a current of 15 amperes, how much current is actually flowing in the circuit ?

27. A dual-voltage three-phase motor draws a current of 45 amperes when connected to a 240-volt, three-phase circuit. How much current will the same motor draw if connected to a 480-volt,three-phase circuit?

28. A synchronous motor has an excitation voltage of 125 volts with a maximum rotor current of 10 amperes. What is the resistance of the motor?

29. The primary of a transformer is connected to 120-volts. There are 30 volts on the secondary with a resistance of 5 ohms. How much current will flow in the primary of the transformer?

30. What current flows in a 60 Hz 120-volt circuit with a capacitance of 10μf (10 microfarads)?

31. What is the total resistance in a 2-wire circuit, 30 feet in length, utilizing No. 10 AWG THWN conductors?

32. If the circuit in Question 31 is connected to a 240-volt source and feeds a load drawing 24 amperes, what is the amount of voltage drop?

33. Referring to Question 32 above, how many volts in the circuit actually reach the load?

34. A circuit consisting of two No. 14 AWG conductors is run from the panelboard to a load 100 feet away. If the K factor is 12.9 and No. 14 wire is equal to 4107 circular mils, what is the total resistance of the circuit?

35. A circuit consisting of two No. 14 AWG conductors is run from the panelboard to a load 100 feet away. If the K factor is 12.9 and No. 14 wire is equal to 4107 circular mils.

What is the voltage drop in the circuit if the current is 24 amperes at 240 volts?

36. A circuit consisting of two No. 14 AWG conductors is run from the panelboard to a load 100 feet away. If the K factor is 12.9 and No. 14 wire is equal to 4107 circular mils.

How much voltage actually reaches the load in the circuit?

37. What is the inductance reactance in a 120-volt, 60 Hz circuit connected to a coil with an inductance of 0.7 henrys?

38. What is the impedance (Z) in a circuit with 40 ohms resistance (R) and 30 ohms inductive reactance (XL)?

39. What is the power factor of a circuit with 400 watts true power, 300 vars reactive power, and 500 watts (volt-amperes) of apparent power?

40. What is the power factor of a 120-volt circuit feeding an AC induction motor drawing 10 amperes of current with a true power of 720 watts and an apparent power of 1200 volt-amperes?

41. What is the reactive power of a 120-volt circuit feeding an AC induction motor drawing 10 amperes of current with a true power of 720 watts and an apparent power of 1200 volt-amperes?

42. What is the capacitive reactance of a 120-volt circuit feeding an AC induction motor drawing 10 amperes of current with a true power of 720 watts and an apparent power of 1200 volt-amperes?

43. What is the amount of capacitance of a 120-volt circuit feeding an AC induction motor drawing 10 amperes of current with a true power of 720 watts and an apparent power of 1200 volt-amperes?

44. What is the total resistance of a series circuit with resistors of 5 ohms, 3 ohms, 12 ohms, and 9 ohms?

45. What is the resistance of a parallel circuit with resistors of 30 ohms and 50 ohms?

46. A 12-volt battery supplies a total load of 10 amperes. What would the amperage be if the battery voltage dropped 10% and the load resistance remained the same?

47. A department store is illuminated with 215 fluorescent lighting fixtures and connected to a 120-volt supply. Each lighting unit draws 2.2 amperes. How many 20-ampere branch circuits are necessary to feed these fixtures if each branch circuit must not exceed 80% of the branch circuit rating?

48. A department store is illuminated with 215 fluorescent lighting fixtures and connected to a 120-volt supply. Each lighting unit draws 2.2 amperes at 0.8 power factor.

What is the total power of the lighting load?

48. A department store is illuminated with 215 fluorescent lighting fixtures and connected to a 120-volt supply. Each lighting unit draws 2.2 amperes at 0.8 power factor.

What would the electric bill be for the lighting load for an 8-hour day if the energy costs 10 cents per kWh?

50. A 60 kW incandescent lighting load is connected to a 120/208-volt, three-phase, 4-wire electric service. The load is balanced. What is the total current consumed by this load?