Test your basic knowledge |

DC Theory

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. What is the equivalent resistance of two 8-ohm resistors connected in parallel?
In series.
4.0 ohms.
Watts.
A. Total resistance is less than the smallest resistor.

2. Trailing cable on DC-powered mobile haulage equipment must be at least...
The movement of electrons in a circuit.
Less than the resistance of either resistor.
400 ampere-hours.
No.4 AWG.

3. What is the total resistance of three 16-ohm resistors connected in series?
Wattmeter.
Voltage.
48 ohms.
Burns will appear only at the point where contact is made to the energized circuit.

4. What is the unit of electromotive force or electric pressure?
Treat for physical shock.
Voltage.
746 watts.
Flush the burn the clean water.

5. What is the total voltage of two 6-volt batteries connected in parallel?
36 volts.
6 volts.
4.0 ohms.
Current that flows in one direction only.

6. What is Ohm's Law?
Ventilation.
A. Total resistance is less than the smallest resistor.
E=IR.
Wattmeter.

7. Current in a series circuit...
Stays the same.
Resistance.
Power.
A bi-directional device that can pass current in either direction.

8. What is the total resistance of four 25-ohm resistors connected in series?
Current that flows in one direction only.
100 ohms
In series.
Higher current with voltage remaining the same.

9. If the victim of an electrical shock has been burned while in contact with electricity - the first treatment you should apply - if the victim's heart and respiratory system are still functioning - is to...
A wire wound resistor.
Treat for physical shock.
Amperes.
Wattmeter.

10. What should be used in treating an eye injury caused by battery acid?
Clean water.
Hydrometer.
Repel each other.
Watts.

11. If the cross-sectional area of a conductor is increased - its resistance will...
15 minutes.
36 volts.
8 ohms.
Decrease.

12. The unit of measurement of power is...
Current.
Watts.
36 volts.
8 ohms.

13. Not true about electrical shocks?
200 volts
8 ohms.
Flush thoroughly with water.
Burns will appear only at the point where contact is made to the energized circuit.

14. The advantage of DC over AC is that DC offers...
Repel each other.
Distance.
Better speed control on motors.
The opposition to flow of electrons in a circuit.

15. Which of the following motors are considered to be constant or nearly constant speed?
Compound-wound and shunt-wound.
Ohms.
75 volts.
Clean water.

16. The armature of a direct current motor - when running - generates...
48 volts
A counter-EMF.
1.260 to 1.280.
Flush the burn the clean water.

17. Like poles of a magnet will...
48 volts
Hydrometer.
Stays the same.
Repel each other.

18. The first step in treating a chemical burn - such as one caused by battery acid - is to...
Flush thoroughly with water.
The opposition to flow of electrons in a circuit.
Soft iron.
Resistance.

19. Which of the following stays the same in all parts of a series circuit?
Current
Burns will appear only at the point where contact is made to the energized circuit.
1.260 to 1.280.
746 watts.

20. What is the equivalent resistance of two 16-ohm resistors connected in parallel?
It must prevent ignition of surrounding methane atmosphere.
There is a hazard of blowing the contents back into your face - 'explosive reaction'.
Resistance.
8 ohms.

21. The specific gravity of the electrolyte of a fully charged battery should be...
Hydrogen.
Current.
Current that flows in one direction only.
1.260 to 1.280.

22. A battery capable of producing 20 amperes steadily for 20 hours at 80 degrees Fahrenheit would have an ampere-hour rating of...
After charging
There is a hazard of blowing the contents back into your face - 'explosive reaction'.
400 ampere-hours.
100 ohms

23. What is the total voltage of four 12-volt batteries connected in series?
No.4 AWG.
Current
48 volts
6 volts.

24. The core of an electro-magnet should be made of...
Soft iron.
No.4 AWG.
500 volts.
Power.

25. What is the rate that work is done or heat is dissipated?
Higher current with voltage remaining the same.
Power.
200 volts
4.0 ohms.

26. Voltage in a parallel circuit...
In parallel.
Hydrogen.
Stays the same.
Clean water.

27. The unit of measurement of current is...
75 volts.
Amperes.
500 volts.
No.4 AWG.

28. What voltage is required to force 5 amps through a 15-ohm resistor?
After charging
75 volts.
60 ohms.
Attract each other.

29. The instrument used to check the electrolyte of a battery is a...
96 volts.
In series.
Amperes.
Hydrometer.

30. What is the first step in treating a chemical burn of the eye?
Resistance.
Hydrogen.
200 volts
Flush the burn the clean water.

31. Resistance is measured with a...
96 volts.
Higher current with voltage remaining the same.
Ohmmeter.
Voltmeter.

32. Not a requirement of an explosion-proof enclosure?
Ventilation.
200 volts
It must prevent internal explosions.
6 volts.

33. Which current flows in only one direction?
Heat
A bi-directional device that can pass current in either direction.
Direct current.
Ammeter.

34. Voltage is measured with a...
200 volts
Voltmeter.
Clean water.
Ventilation.

35. What is the hazard of pouring water into battery acid 'electrolyte'?

Warning: Invalid argument supplied for foreach() in /var/www/html/basicversity.com/show_quiz.php on line 183

36. What is the flow of electrons in a conductor?
Current.
Decrease.
Better speed control on motors.
500 volts.

37. A triac is?
Heat
A bi-directional device that can pass current in either direction.
6 volts.
Hydrogen.

38. Define direct current...
Repel each other.
48 volts
Current that flows in only one direction.
48 ohms.

39. What is the total resistance of four 15-ohm resistors connected in series?
Stays the same.
Until the victim receives medical attention.
60 ohms.
Power.

40. When should water be added to a battery?
Series-wound.
After charging
Voltmeter.
Flush thoroughly with water.

41. Current is measured with a (an)...
Ammeter.
A wire wound resistor.
Ventilation.
Higher current with voltage remaining the same.

42. How many kilowatts are used to develop 50 horsepower?
Compound-wound and shunt-wound.
A bi-directional device that can pass current in either direction.
37.3 kilowatts
Burns will appear only at the point where contact is made to the energized circuit.

43. Not an electro-magnet?
A wire wound resistor.
Burns will appear only at the point where contact is made to the energized circuit.
Current that flows in only one direction.
Higher current with voltage remaining the same.

44. Define direct current...
Current that flows in one direction only.
Ammeter.
A. Total resistance is less than the smallest resistor.
8 ohms.

45. Unlike poles of a magnet will...
The opposition to flow of electrons in a circuit.
Attract each other.
Flush the burn the clean water.
Compound-wound and shunt-wound.

46. Resistors are rated in ohms and...
Watts.
48 ohms.
1.260 to 1.280.
The opposition to flow of electrons in a circuit.

47. How many watts are in one horsepower?
Direct current.
No.4 AWG.
746 watts.
Flush the burn the clean water.

48. The dangerously explosive gas emitted by charging a lead-acid storage battery is...
Hydrogen.
It must prevent internal explosions.
Higher current with voltage remaining the same.
Voltmeter.

49. Define resistance...
The opposition to flow of electrons in a circuit.
200 volts
Soft iron.
75 volts.

50. The minimum allowable size of trailing cable on DC-powered mobile haulage equipment is...
36 volts.
No.4 AWG.
48 ohms.
100 ohms