Deep Dive: T0A02
The correct answer is D: All these choices are correct. Electrical current flowing through the body can cause injury by heating tissue, disrupting electrical functions of cells, and causing involuntary muscle contractions. All three are serious hazards. Current heats tissue (causing burns), interferes with nerve and muscle function (potentially stopping the heart), and causes muscles to contract (preventing you from letting go). For amateur radio operators, understanding these hazards emphasizes the importance of electrical safety. Even relatively low currents can be dangerous or fatal.
Why Other Answers Are Wrong
Option A: While correct, this is incomplete. Current also disrupts cell functions and causes muscle contractions. Option B: While correct, this is incomplete. Current also heats tissue and causes muscle contractions. Option C: While correct, this is incomplete. Current also heats tissue and disrupts cell functions.
Exam Tip
All three are hazards: tissue heating, cell disruption, muscle contractions. When all listed effects are valid hazards of electrical current, 'all of the above' is usually the answer. All can cause serious injury or death.
Memory Aid
All three are hazards: Tissue heating, Cell disruption, Muscle contractions. Think 'A'll 'C'urrent 'H'azards. Electrical current through the body can cause burns, disrupt heart rhythm, and cause muscle contractions - all dangerous.
Real-World Example
You accidentally touch a live 120V AC wire. Current flows through your body, (1) heating tissue and causing burns at entry/exit points, (2) disrupting your heart's electrical rhythm (potentially causing cardiac arrest), and (3) causing your muscles to contract, making it difficult or impossible to let go. All three effects are dangerous and can be fatal.
Source & Coverage
Question Pool: 2022-2026 Question Pool
Subelement: T0A
Reference: 2022-2026 Question Pool · T0 - Safety
Key Concepts
Verified Content
Question from the official FCC Technician Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the T0A topic.