Bennett Mechanical Comprehension Practice Test 2026 - Free Practice Questions and Review Guide

The correct choice is based on the principle of energy conversion in electrical appliances. An electric iron is designed to convert electrical energy into thermal energy (heat) through a process called resistive heating or Joule heating. This occurs as electricity flows through the heating element of the iron, which has a high resistance. The resistance causes the electrical energy to be transformed into heat, thus raising the temperature of the iron.

In contrast, the cable connecting the electric iron to the power source is designed to conduct electricity efficiently without generating significant heat. It typically has a much lower resistance compared to the heating element of the iron. Consequently, while the iron heats up, the cable remains cool because it is not meant to convert electricity into heat; instead, it is designed solely to carry the electrical current.

This reflects fundamental principles in electrical engineering, where the design of components dictates their function and thermal behavior during operation.