What is the current through a 100-ohm resistor connected across 200 volts?
The correct answer is C: 2 amperes. The current through a 100-ohm resistor connected across 200 volts is 2 amperes. Using Ohm's Law: I = E / R = 200 / 100 = 2 amperes.
This is a straightforward application of Ohm's Law to find current. When a 100-ohm resistor is connected across 200 volts, the current is 2 amperes. This calculation is fundamental for understanding circuit behavior and calculating power (P = E × I = 200 × 2 = 400 watts). The formula I = E / R shows that current is directly proportional to voltage and inversely proportional to resistance.
Exam Tip
Current = Voltage / Resistance. Remember: I = 200V / 100Ω = 2A. Simple division gives the answer.
Memory Aid
"**I** = **2**00V / **1**00Ω = **2**A (think '200/100 = 2')"
Real-World Application
You're testing a dummy load. You connect a 100-ohm resistor across 200 volts. Using I = E / R, you calculate the current: I = 200 / 100 = 2 amperes. This helps you verify the load and calculate power dissipation (400 watts).
Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. 20,000 amperes would be multiplying voltage and resistance (200 × 100), which is mathematically incorrect. Current is voltage divided by resistance.
Option B: Incorrect. 0.5 amperes would be dividing resistance by voltage (100 / 200), which is the inverse of the correct formula.
Option D: Incorrect. 100 amperes would be using the resistance value as current, which doesn't follow Ohm's Law.
题目解析
The correct answer is C: 2 amperes. The current through a 100-ohm resistor connected across 200 volts is 2 amperes. Using Ohm's Law: I = E / R = 200 / 100 = 2 amperes. This is a straightforward application of Ohm's Law to find current. When a 100-ohm resistor is connected across 200 volts, the current is 2 amperes. This calculation is fundamental for understanding circuit behavior and calculating power (P = E × I = 200 × 2 = 400 watts). The formula I = E / R shows that current is directly proportional to voltage and inversely proportional to resistance.
考试技巧
Current = Voltage / Resistance. Remember: I = 200V / 100Ω = 2A. Simple division gives the answer.
记忆口诀
**I** = **2**00V / **1**00Ω = **2**A (think '200/100 = 2')
实际应用示例
You're testing a dummy load. You connect a 100-ohm resistor across 200 volts. Using I = E / R, you calculate the current: I = 200 / 100 = 2 amperes. This helps you verify the load and calculate power dissipation (400 watts).
错误选项分析
Option A: Incorrect. 20,000 amperes would be multiplying voltage and resistance (200 × 100), which is mathematically incorrect. Current is voltage divided by resistance. Option B: Incorrect. 0.5 amperes would be dividing resistance by voltage (100 / 200), which is the inverse of the correct formula. Option D: Incorrect. 100 amperes would be using the resistance value as current, which doesn't follow Ohm's Law.
知识点
Ohm's Law calculation, Current calculation, I = E / R, Resistor current
Verified Content
Question from official FCC Technician Class question pool. Explanation reviewed by licensed amateur radio operators.