Oral Question Review
Basic Electricity
1. One kilowatt is equal to how many watts?
Answer—1,000 watts.

2. What law describes the most fundamental or basic relationships in an electrical circuit?
Answer—Ohm’s law.

3. What are the three elements of Ohm’s law?
Answer—voltage (E), current (I), and resistance (R). 4. How would you write Ohm’s law as an equation?
Answer— or or

5. If the resistance in a DC circuit remains the same but the voltage doubles, what happens to the amount of current flowing in the circuit?
Answer—it also doubles.

6. In DC circuits, what unit measures power?
Answer—watts. Amperes times volts equals watts (). 746 watts equals 1 horsepower.

7. What three elements are required to form an electrical circuit?
Answer—a source of electrical pressure (energy) or EMF, resistance in the form of an energy consuming electrical device, and conductors, usually in the form of copper or aluminum wires, to provide a path for electrical flow.

8. DC circuits can take one of three forms or types. What are they?
Answer—series, parallel, and complex (series-parallel).

9. What are the sources of electrical energy?
Answer—mechanical (generator), chemical (battery), photoelectric (light), and thermal (heat).

10. A 24-volt lead-acid battery has how many cells?
Answer—12 cells. Each cell is rated at 2 volts.

11. A fully charged lead-acid battery has a specific gravity that varies between what two values?
Answer—1.275 and 1.300.

12. You must apply a correction to the specific gravity reading of the electrolyte of a lead-acid battery when the temperature is outside of what two values?
Answer—less than 70F or more than 90F.
13. What is the reason for having separate facilities for storing and servicing nickel-cadmium and lead-acid batteries?
Answer—the electrolyte in the two types of batteries is chemically opposite and the fumes from one type can contaminate the electrolyte of the other type.

14. The state of charge of a nickel-cadmium battery cannot be determined by measuring the specific gravity of the electrolyte for what reason?
Answer—there is no significant change in the specific gravity of the electrolyte as the battery is charged or discharged.

15. What instrument is used to determine the specific gravity of electrolyte in a lead-acid battery?
Answer—a hydrometer.

16. Why can’t a hydrometer be used to determine the charge of a nickel-cadmium battery?
Answer—the specific gravity of the electrolyte in a nickel-cadmium battery does not change appreciably during charge or discharge of the battery.

17. How are battery compartments protected against corrosion?
Answer—they are coated with special corrosion resistant paints such as bituminous paint.

18. What should be the correct electrolyte level in a properly serviced battery?
Answer—it should be approximately 3/8 inches above the plates. If the battery has baffle