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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. The unit of measurement of current is...
Stays the same.
Attract each other.
In parallel.
Amperes.

2. What is the rate that work is done or heat is dissipated?
Wattmeter.
4.0 ohms.
In series.
Power.

3. What should be used in treating an eye injury caused by battery acid?
Distance.
It must prevent internal explosions.
Clean water.
48 volts

4. What must be provided at underground battery charging stations?
Clean water.
48 volts
Ohms.
Ventilation.

5. What is the total resistance of four 25-ohm resistors connected in series?
Higher current with voltage remaining the same.
100 ohms
Until the victim receives medical attention.
The movement of electrons in a circuit.

6. Which of the following stays the same in all parts of a series circuit?
Flush thoroughly with water.
Current
Higher current with voltage remaining the same.
The opposition to flow of electrons in a circuit.

7. Current in a series circuit...
Clean water.
48 volts
The opposition to flow of electrons in a circuit.
Stays the same.

8. The most common reason that solid state devices fail is...
400 ampere-hours.
100 ohms
Heat
Voltage.

9. Define current...
There is a hazard of blowing the contents back into your face - 'explosive reaction'.
The movement of electrons in a circuit.
4.0 ohms.
Watts.

10. The best insulator against the lines of magnetic force is...
Flush thoroughly with water.
Compound-wound and shunt-wound.
Distance.
4.8 ohms

11. Voltage is measured with a...
200 volts
E=IR.
Decrease.
Voltmeter.

12. What is the equivalent resistance of an 8-ohm and a 12-ohm resistor connected in parallel?
Repel each other.
4.8 ohms
500 volts.
Hydrogen.

13. What is the unit of electromotive force or electric pressure?
37.3 kilowatts
Voltage.
400 ampere-hours.
15 minutes.

14. What is the opposition to flow of electric current?
6 volts.
Decrease.
Clean water.
Resistance.

15. What is the total resistance of three 16-ohm resistors connected in series?
Heat
48 ohms.
No.4 AWG.
Voltmeter.

16. How must two 12-volt batteries be connected in order to increase the current capacity?
Watts.
Voltage.
Hydrometer.
In parallel.

17. Resistance is measured with a...
Current that flows in only one direction.
Ohmmeter.
Repel each other.
15 minutes.

18. Not true about electrical shocks?
Burns will appear only at the point where contact is made to the energized circuit.
In series.
200 volts
8 ohms.

19. If the cross-sectional area of a conductor is increased - its resistance will...
Decrease.
In parallel.
Current
1.260 to 1.280.

20. What voltage would be required to force 10 amps through a 20-ohm resistor?
Current that flows in only one direction.
Ohms.
200 volts
Less than the resistance of either resistor.

21. 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...
400 ampere-hours.
Treat for physical shock.
Series-wound.
Hydrogen.

22. Which of the following motors are considered to be constant or nearly constant speed?
Power.
Less than the resistance of either resistor.
Compound-wound and shunt-wound.
After charging

23. What is the total resistance of four 15-ohm resistors connected in series?
Repel each other.
Treat for physical shock.
60 ohms.
Series-wound.

24. What is the equivalent resistance of two 16-ohm resistors connected in parallel?
8 ohms.
400 ampere-hours.
Better speed control on motors.
36 volts.

25. Resistors are rated in ohms and...
Ohms.
Watts.
Until the victim receives medical attention.
36 volts.

26. Trailing cable on DC-powered mobile haulage equipment must be at least...
Ohms.
A counter-EMF.
No.4 AWG.
1.260 to 1.280.

27. The advantage of DC over AC is that DC offers...
15 minutes.
Better speed control on motors.
Watts.
Hydrometer.

28. Batteries connected in parallel provide...
Flush thoroughly with water.
75 volts.
Until the victim receives medical attention.
Higher current with voltage remaining the same.

29. What voltage would be required to force 10 amps through a 50-ohm resistor?
Voltmeter.
Current
Current.
500 volts.

30. Unlike poles of a magnet will...
Attract each other.
Voltage.
In series.
Flush thoroughly with water.

31. What is the total voltage of four 9-volt batteries connected in a series?
1.260 to 1.280.
36 volts.
Watts.
48 ohms.

32. In a parallel circuit...
Current.
The opposition to flow of electrons in a circuit.
A. Total resistance is less than the smallest resistor.
Heat

33. Define direct current...
In series.
Distance.
Amperes.
Current that flows in only one direction.

34. What is the total voltage of four 12-volt batteries connected in series?
48 volts
500 volts.
Compound-wound and shunt-wound.
Stays the same.

35. Storage battery charging stations must be provided with what kind of current protection?
Reverse.
There is a hazard of blowing the contents back into your face - 'explosive reaction'.
200 volts
Current that flows in only one direction.

36. You have three 9-volt batteries. How should you connect them in order to supply 27 volts?
E=IR.
In series.
Flush thoroughly with water.
Compound-wound and shunt-wound.

37. Chemical burns caused by battery acid should be washed with clean water for at least...
Ohmmeter.
Current that flows in one direction only.
15 minutes.
Resistance.

38. Voltage in a parallel circuit...
48 ohms.
Stays the same.
Decrease.
400 ampere-hours.

39. What is the total voltage of eight 12-volt batteries connected in series?
96 volts.
Clean water.
Power.
Soft iron.

40. The longer the conductor - the greater the...
Resistance.
8 ohms.
Decrease.
No.4 AWG.

41. How long should treatment for shock be continued?
75 volts.
Until the victim receives medical attention.
Decrease.
Hydrometer.

42. What is the flow of electrons in a conductor?
500 volts.
6 volts.
Current.
Attract each other.

43. The dangerously explosive gas emitted by charging a lead-acid storage battery is...
Stays the same.
Watts.
Attract each other.
Hydrogen.

44. The specific gravity of the electrolyte of a fully charged battery should be...
500 volts.
Power.
96 volts.
1.260 to 1.280.

45. The explosive gas that is generated when a battery is charging is...
In series.
E=IR.
In series.
Hydrogen.

46. The minimum allowable size of trailing cable on DC-powered mobile haulage equipment is...
E=IR.
No.4 AWG.
The movement of electrons in a circuit.
Current that flows in one direction only.

47. Which current flows in only one direction?
746 watts.
No.4 AWG.
Soft iron.
Direct current.

48. Power is measured with a...
Wattmeter.
Voltmeter.
The opposition to flow of electrons in a circuit.
Stays the same.

49. Define direct current...
Hydrometer.
Soft iron.
Repel each other.
Current that flows in one direction only.

50. Not a requirement of an explosion-proof enclosure?
Heat
Reverse.
A counter-EMF.
It must prevent internal explosions.