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LADWP ELECTRIC STATION OPERATOR CERTIFICATION EXAM; 300 ESSENTIAL QUESTIONS AND ANSWERS COVERING ELECTRICAL SYSTEMS, POWER GENERATION, TRANSMISSION, PROTECTION, AND SAFETY 1. Q: What is Ohm's Law? A: Ohm's Law states that V = I × R, where V is voltage, I is current, and R is resistance. 2. Q: What is the relationship between voltage, current, and power? A: Power (P) = Voltage (V) × Current (I), or P = V × I. 3. Q: What is AC voltage? A: Alternating Current (AC) voltage is electrical voltage that periodically reverses direction, typically at 60 Hz in the US. 4. Q: What is DC voltage? A: Direct Current (DC) voltage is electrical voltage that flows in one constant direction. 5. Q: What is the standard frequency for AC power in the United States? A: 60 Hz (60 cycles per second). 6. Q: What is a transformer? A: A transformer is a device that transfers electrical energy between circuits through electromagnetic induction, typically used to step voltage up or down. 7. Q: What is the difference between a step-up and step-down transformer? A: A step-up transformer increases voltage while decreasing current; a stepdown transformer decreases voltage while increasing current. 8. Q: What is power factor? A: Power factor is the ratio of real power to apparent power, indicating how effectively electrical power is being used. 9. Q: What is reactive power? A: Reactive power is the portion of electrical power that does not perform useful work but is needed to maintain voltage levels for power transmission. 10. Q: What is impedance? A: Impedance is the total opposition to current flow in an AC circuit, combining resistance and reactance.