How much power is being absorbed by the load when a directional power meter connected between a transmitter and a terminating load reads 100 watts forward power and 25 watts reflected power?
The correct answer is D: 75 watts. How much power is being absorbed by the load when a directional power meter connected between a transmitter and a terminating load reads 100 watts forward power and 25 watts reflected power is 75 watts. Absorbed power = forward - reflected = 100 - 25 = 75 watts. For amateur radio operators, this is important for power measurements. Understanding this helps when measuring power.
Exam Tip
Absorbed power = forward power - reflected power. Think 'A'bsorbed = 'F'orward - 'R'eflected. Absorbed power = 100 - 25 = 75 watts. Not 100W (forward), not 125W (sum), not 112.5W - just 75 watts (difference).
Memory Aid
"Absorbed power = forward power - reflected power. Think 'A'bsorbed = 'F'orward - 'R'eflected. Absorbed power = 100 - 25 = 75 watts. Important for power measurements."
Real-World Application
A directional power meter reads 100 watts forward and 25 watts reflected: The power absorbed by the load is forward power minus reflected power = 100 - 25 = 75 watts. The reflected power is lost, so only the difference is absorbed. This is the calculation - 75 watts absorbed.
Key Concepts
Why Other Options Are Wrong
Option A (100 watts): Incorrect. 100 watts is forward power, not absorbed - absorbed = forward - reflected = 75 watts. 100 watts is forward.
Option B (125 watts): Incorrect. 125 watts is forward + reflected, not absorbed - absorbed = forward - reflected = 75 watts. 125 watts is wrong.
Option C (112.5 watts): Incorrect. 112.5 watts isn't the calculation - absorbed = forward - reflected = 100 - 25 = 75 watts. 112.5 watts is wrong.
题目解析
The correct answer is D: 75 watts. How much power is being absorbed by the load when a directional power meter connected between a transmitter and a terminating load reads 100 watts forward power and 25 watts reflected power is 75 watts. Absorbed power = forward - reflected = 100 - 25 = 75 watts. For amateur radio operators, this is important for power measurements. Understanding this helps when measuring power.
考试技巧
Absorbed power = forward power - reflected power. Think 'A'bsorbed = 'F'orward - 'R'eflected. Absorbed power = 100 - 25 = 75 watts. Not 100W (forward), not 125W (sum), not 112.5W - just 75 watts (difference).
记忆口诀
Absorbed power = forward power - reflected power. Think 'A'bsorbed = 'F'orward - 'R'eflected. Absorbed power = 100 - 25 = 75 watts. Important for power measurements.
实际应用示例
A directional power meter reads 100 watts forward and 25 watts reflected: The power absorbed by the load is forward power minus reflected power = 100 - 25 = 75 watts. The reflected power is lost, so only the difference is absorbed. This is the calculation - 75 watts absorbed.
错误选项分析
Option A (100 watts): Incorrect. 100 watts is forward power, not absorbed - absorbed = forward - reflected = 75 watts. 100 watts is forward. Option B (125 watts): Incorrect. 125 watts is forward + reflected, not absorbed - absorbed = forward - reflected = 75 watts. 125 watts is wrong. Option C (112.5 watts): Incorrect. 112.5 watts isn't the calculation - absorbed = forward - reflected = 100 - 25 = 75 watts. 112.5 watts is wrong.
知识点
Directional power meter, Forward power, Reflected power, Absorbed power, 75 watts
Verified Content
Question from official FCC Extra Class question pool. Explanation reviewed by licensed amateur radio operators.