What is the resistance of a circuit for which the applied voltage is 12 volts and the current flow is 1.5 amperes?
The correct answer is C: 8 ohms. For a circuit with applied voltage of 12 volts and current flow of 1.5 amperes, the resistance is 8 ohms. Using Ohm's Law: R = E / I = 12 / 1.5 = 8 ohms.
This calculation demonstrates how to find resistance when you know voltage and current. The formula R = E / I is straightforward: divide 12 volts by 1.5 amperes to get 8 ohms. This type of calculation is essential for understanding circuit behavior, selecting proper components, and troubleshooting. The result shows that an 8-ohm resistor will allow 1.5 amperes to flow when 12 volts is applied.
Exam Tip
Resistance = Voltage / Current. Remember: R = 12V / 1.5A = 8 ohms. Divide voltage by current, not the other way around.
Memory Aid
"**R** = **1**2V / **1**.**5**A = **8**Ω (think '12/1.5 = 8')"
Real-World Application
You're testing a 12-volt power supply. You connect a load and measure 1.5 amperes of current. Using R = E / I, you calculate the load resistance: R = 12 / 1.5 = 8 ohms. This confirms the load value and helps you verify proper operation.
Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. 18 ohms would be multiplying voltage and current (12 × 1.5), which gives power (18 watts), not resistance.
Option B: Incorrect. 0.125 ohms would be dividing current by voltage (1.5 / 12), which is the inverse of the correct formula.
Option D: Incorrect. 13.5 ohms would be adding voltage and current (12 + 1.5), which is mathematically incorrect.
题目解析
The correct answer is C: 8 ohms. For a circuit with applied voltage of 12 volts and current flow of 1.5 amperes, the resistance is 8 ohms. Using Ohm's Law: R = E / I = 12 / 1.5 = 8 ohms. This calculation demonstrates how to find resistance when you know voltage and current. The formula R = E / I is straightforward: divide 12 volts by 1.5 amperes to get 8 ohms. This type of calculation is essential for understanding circuit behavior, selecting proper components, and troubleshooting. The result shows that an 8-ohm resistor will allow 1.5 amperes to flow when 12 volts is applied.
考试技巧
Resistance = Voltage / Current. Remember: R = 12V / 1.5A = 8 ohms. Divide voltage by current, not the other way around.
记忆口诀
**R** = **1**2V / **1**.**5**A = **8**Ω (think '12/1.5 = 8')
实际应用示例
You're testing a 12-volt power supply. You connect a load and measure 1.5 amperes of current. Using R = E / I, you calculate the load resistance: R = 12 / 1.5 = 8 ohms. This confirms the load value and helps you verify proper operation.
错误选项分析
Option A: Incorrect. 18 ohms would be multiplying voltage and current (12 × 1.5), which gives power (18 watts), not resistance. Option B: Incorrect. 0.125 ohms would be dividing current by voltage (1.5 / 12), which is the inverse of the correct formula. Option D: Incorrect. 13.5 ohms would be adding voltage and current (12 + 1.5), which is mathematically incorrect.
知识点
Ohm's Law calculation, Resistance, R = E / I, Circuit analysis
Verified Content
Question from official FCC Technician Class question pool. Explanation reviewed by licensed amateur radio operators.