How does duration affect electrical shock severity?

• A. The effect of duration is negligible unless the current is above 1000 mA.
• B. The duration of current has no impact on injury under any circumstances.
• C. Even currents as low as 20 mA can cause significant damage or be fatal if sustained for a period.
• D. Short duration always causes more damage than long duration.

Answer: (C)

The main idea is that how long a current flows through the body matters as much as how strong it is. The body absorbs energy from the electrical current, and this energy turns into heat and can disrupt nerves, muscle control, and heart rhythms. The longer the current flows, the more energy is deposited, so the greater the potential for injury.

Even a relatively small current, like about 20 mA, can cause serious damage or be fatal if it is sustained for a few seconds or longer. At this level, muscles can seize, making it hard or impossible to let go of the source, which can prolong exposure. With enough duration, the risk of dangerous heart rhythms increases, leading to potentially fatal outcomes.

Short, brief shocks are less likely to cause long-term harm, but extensions of exposure time raise the danger significantly. This is why duration is a critical factor in electrical injury—it's not enough to look at current alone.