What is the voltage across a 10-ohm resistor if a current of 2 amperes flows through it?
The correct answer is D: 20 volts. The voltage across a 10-ohm resistor if a current of 2 amperes flows through it is 20 volts. Using Ohm's Law: E = I × R = 2 × 10 = 20 volts.
This is a direct application of Ohm's Law to find voltage. When 2 amperes flows through a 10-ohm resistor, the voltage across it is 20 volts. 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, which is essential for circuit design and troubleshooting.
Exam Tip
Voltage = Current × Resistance. Remember: E = 2A × 10Ω = 20V. Multiply current by resistance to find voltage.
Memory Aid
"**E** = **2**A × **1**0Ω = **2**0V (think '2×10 = 20')"
Real-World Application
You're testing a circuit. You measure 2 amperes flowing through a 10-ohm resistor. Using E = I × R, you calculate the voltage: E = 2 × 10 = 20 volts. This helps you verify the circuit operation and understand power dissipation (40 watts).
Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. 8 volts would be subtracting current from resistance (10 - 2), which is mathematically invalid. Voltage must be calculated as current times resistance.
Option B: Incorrect. 0.2 volts would be dividing current by resistance (2 / 10), which is the inverse of the correct formula.
Option C: Incorrect. 12 volts would be adding current and resistance (2 + 10), which is mathematically invalid.
题目解析
The correct answer is D: 20 volts. The voltage across a 10-ohm resistor if a current of 2 amperes flows through it is 20 volts. Using Ohm's Law: E = I × R = 2 × 10 = 20 volts. This is a direct application of Ohm's Law to find voltage. When 2 amperes flows through a 10-ohm resistor, the voltage across it is 20 volts. 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, which is essential for circuit design and troubleshooting.
考试技巧
Voltage = Current × Resistance. Remember: E = 2A × 10Ω = 20V. Multiply current by resistance to find voltage.
记忆口诀
**E** = **2**A × **1**0Ω = **2**0V (think '2×10 = 20')
实际应用示例
You're testing a circuit. You measure 2 amperes flowing through a 10-ohm resistor. Using E = I × R, you calculate the voltage: E = 2 × 10 = 20 volts. This helps you verify the circuit operation and understand power dissipation (40 watts).
错误选项分析
Option A: Incorrect. 8 volts would be subtracting current from resistance (10 - 2), which is mathematically invalid. Voltage must be calculated as current times resistance. Option B: Incorrect. 0.2 volts would be dividing current by resistance (2 / 10), which is the inverse of the correct formula. Option C: Incorrect. 12 volts would be adding current and resistance (2 + 10), 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.