Question 43

The Correct Answer is A. ### Explanation for Option A (Correct Answer) **Option A (3 to 7 mA) is correct** because this range represents the generally accepted threshold for the onset of pain and the distinct perception of an electric shock (the "painful sensation"). * The **"let-go" current** (the maximum current an average person can tolerate while still being able to release the energized object) usually starts around 9 mA for women and 16 mA for men. * The threshold of perception (a slight tingle) is typically around 1 mA. * The current level of 3 to 7 mA is significantly above the perception threshold but below the average let-go current, placing it squarely in the zone where the sensation is distinctly painful or shocking, but usually not immediately incapacitating. This is the minimum threshold that produces the painful electric shock sensation most people perceive. ### Explanation of Incorrect Options **Option B (10 to 16 mA) is incorrect** because while this current range is certainly painful and shocking, it represents the average **"let-go" threshold** (the point where muscular contraction is so severe that the person cannot voluntarily release the conductor). The question asks for the *minimum threshold* that *produces* the painful sensation, which occurs at a lower current (3–7 mA). **Option C (30 mA) is incorrect** because this level of current is dangerous and can cause severe respiratory paralysis or ventricular fibrillation if the current path crosses the chest. It is far above the minimum threshold for simply perceiving a painful shock. **Option D (100 mA for 2.5 sec.) is incorrect** because this current level is considered extremely dangerous (lethal). 100 mA passing through the heart area is the general threshold for inducing ventricular fibrillation, especially over a sustained period like 2.5 seconds. This is a lethal threshold, not the minimum threshold for perceiving pain.