Deep Dive: T5D11
The correct answer is B: 10 volts. The voltage across a 10-ohm resistor if a current of 1 ampere flows through it is 10 volts. Using Ohm's Law: E = I × R = 1 × 10 = 10 volts. This is a straightforward application of Ohm's Law. When 1 ampere flows through a 10-ohm resistor, the voltage across it is 10 volts. This calculation is essential for understanding circuit behavior and verifying component operation. The formula E = I × R shows that voltage equals current times resistance, which is the fundamental relationship in DC circuits.
Why Other Answers Are Wrong
Option A: Incorrect. 1 volt would be using the current value as voltage, which doesn't follow Ohm's Law. Voltage must be calculated as current times resistance. Option C: Incorrect. 11 volts would be adding current and resistance (1 + 10), which is mathematically invalid. Option D: Incorrect. 9 volts would be subtracting current from resistance (10 - 1), which is mathematically invalid.
Exam Tip
Voltage = Current × Resistance. Remember: E = 1A × 10Ω = 10V. Multiply current by resistance to find voltage.
Memory Aid
**E** = **1**A × **1**0Ω = **1**0V (think '1×10 = 10')
Real-World Example
You're testing a power supply circuit. You measure 1 ampere flowing through a 10-ohm resistor. Using E = I × R, you calculate the voltage: E = 1 × 10 = 10 volts. This helps you verify the circuit operation and understand power dissipation (10 watts).
Source & Coverage
Question Pool: 2022-2026 Question Pool
Subelement: T5D
Reference: 2022-2026 Question Pool · T5 - Electrical principles
Key Concepts
Verified Content
Question from the official FCC Technician Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the T5D topic.