What is the voltage across a 2-ohm resistor if a current of 0.5 amperes flows through it?
The correct answer is A: 1 volt. The voltage across a 2-ohm resistor if a current of 0.5 amperes flows through it is 1 volt. Using Ohm's Law: E = I × R = 0.5 × 2 = 1 volt.
This is a direct application of Ohm's Law to find voltage. When 0.5 amperes flows through a 2-ohm resistor, the voltage across it is 1 volt. This calculation is fundamental for understanding circuit behavior and verifying component operation. The formula E = I × R shows that voltage is directly proportional to both current and resistance.
Exam Tip
Voltage = Current × Resistance. Remember: E = 0.5A × 2Ω = 1V. Multiply current by resistance to find voltage.
Memory Aid
"**E** = **0**.**5**A × **2**Ω = **1**V (think '0.5×2 = 1')"
Real-World Application
You're testing a circuit. You measure 0.5 amperes flowing through a 2-ohm resistor. Using E = I × R, you calculate the voltage: E = 0.5 × 2 = 1 volt. This helps you verify the circuit operation and understand power dissipation.
Key Concepts
Why Other Options Are Wrong
Option B: Incorrect. 0.25 volts would be dividing current by resistance (0.5 / 2), which is the inverse of the correct formula.
Option C: Incorrect. 2.5 volts would be adding current and resistance (0.5 + 2), which is mathematically invalid.
Option D: Incorrect. 1.5 volts would be subtracting resistance from current (2 - 0.5), which is mathematically invalid.
题目解析
The correct answer is A: 1 volt. The voltage across a 2-ohm resistor if a current of 0.5 amperes flows through it is 1 volt. Using Ohm's Law: E = I × R = 0.5 × 2 = 1 volt. This is a direct application of Ohm's Law to find voltage. When 0.5 amperes flows through a 2-ohm resistor, the voltage across it is 1 volt. This calculation is fundamental for understanding circuit behavior and verifying component operation. The formula E = I × R shows that voltage is directly proportional to both current and resistance.
考试技巧
Voltage = Current × Resistance. Remember: E = 0.5A × 2Ω = 1V. Multiply current by resistance to find voltage.
记忆口诀
**E** = **0**.**5**A × **2**Ω = **1**V (think '0.5×2 = 1')
实际应用示例
You're testing a circuit. You measure 0.5 amperes flowing through a 2-ohm resistor. Using E = I × R, you calculate the voltage: E = 0.5 × 2 = 1 volt. This helps you verify the circuit operation and understand power dissipation.
错误选项分析
Option B: Incorrect. 0.25 volts would be dividing current by resistance (0.5 / 2), which is the inverse of the correct formula. Option C: Incorrect. 2.5 volts would be adding current and resistance (0.5 + 2), which is mathematically invalid. Option D: Incorrect. 1.5 volts would be subtracting resistance from current (2 - 0.5), which is mathematically invalid.
知识点
Ohm's Law calculation, Voltage calculation, E = I × R, Resistor voltage
Verified Content
Question from official FCC Technician Class question pool. Explanation reviewed by licensed amateur radio operators.