Electrical power is measured in which of the following units?
The correct answer is B: Watts. Electrical power is measured in watts (abbreviated as 'W'). Power represents the rate at which electrical energy is used or converted - how much energy per unit time.
Power is calculated as Voltage × Current (P = E × I). One watt equals one joule per second. When you see specifications like '50 watts output' or '100W transmitter', that's referring to electrical power. Power is important in amateur radio for understanding transmitter output, power supply requirements, and energy consumption. Watt-hours (Wh) measure energy (power × time), not power itself.
Exam Tip
Power = Watts. Remember: Electrical power is measured in watts (W). Power is the rate of energy use, while watt-hours measure total energy.
Memory Aid
"**P**ower = **W**atts (think 'P = W' = Power = Watts)"
Real-World Application
Your transceiver outputs 50 watts of RF power when transmitting. This means it's using electrical energy at a rate of 50 watts. If you transmit for 1 hour, you've used 50 watt-hours of energy. The 'watts' tells you the power (rate), while 'watt-hours' tells you the total energy consumed over time.
FCC Part 97.313Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. Volts measure voltage, not power. Voltage is electrical pressure, while power is the rate of energy use.
Option C: Incorrect. Watt-hours measure energy (power × time), not power itself. Power is measured in watts, energy in watt-hours.
Option D: Incorrect. Amperes measure current, not power. Power = Voltage × Current, so you need both voltage and current to calculate power.
题目解析
The correct answer is B: Watts. Electrical power is measured in watts (abbreviated as 'W'). Power represents the rate at which electrical energy is used or converted - how much energy per unit time. Power is calculated as Voltage × Current (P = E × I). One watt equals one joule per second. When you see specifications like '50 watts output' or '100W transmitter', that's referring to electrical power. Power is important in amateur radio for understanding transmitter output, power supply requirements, and energy consumption. Watt-hours (Wh) measure energy (power × time), not power itself.
考试技巧
Power = Watts. Remember: Electrical power is measured in watts (W). Power is the rate of energy use, while watt-hours measure total energy.
记忆口诀
**P**ower = **W**atts (think 'P = W' = Power = Watts)
实际应用示例
Your transceiver outputs 50 watts of RF power when transmitting. This means it's using electrical energy at a rate of 50 watts. If you transmit for 1 hour, you've used 50 watt-hours of energy. The 'watts' tells you the power (rate), while 'watt-hours' tells you the total energy consumed over time.
错误选项分析
Option A: Incorrect. Volts measure voltage, not power. Voltage is electrical pressure, while power is the rate of energy use. Option C: Incorrect. Watt-hours measure energy (power × time), not power itself. Power is measured in watts, energy in watt-hours. Option D: Incorrect. Amperes measure current, not power. Power = Voltage × Current, so you need both voltage and current to calculate power.
知识点
Electrical power, Watts, Power measurement, Electrical units
Verified Content
Question from official FCC Technician Class question pool. Explanation reviewed by licensed amateur radio operators.