How does the distance from an arc source affect thermal energy exposure?

The selected answer is correct because, in the context of thermal energy exposure from an arc source, the principle of inverse square law applies. As the distance from the arc increases, the intensity of thermal energy, which can cause injury or burns, diminishes significantly. This occurs because the thermal energy radiates outward from the arc source, and as the distance increases, that energy spreads over a larger area, resulting in a lower energy density at further points.

Therefore, a worker positioned farther from the arc source experiences less thermal energy, reducing the risk of thermal injuries. Understanding this principle is essential for ensuring the safety of workers near electrical arc hazards, allowing them to maintain a safe distance and minimize potential exposure to harmful thermal effects.