Final answer:
DCEN current is most effective for deep penetration, often used in welding. In contrast, automobiles use direct current (DC) systems. DC is a constant flow of charge, while AC flows in alternating directions and varies periodically.
Step-by-step explanation:
The question asks about which type of current is most effective for achieving the best penetration. Among the options given, DCEN current (Direct Current Electrode Negative) is often considered the most effective for deep penetration in welding applications. This type of current ensures that the electrode becomes the negative pole, which increases the heat concentration on the workpiece and thus results in deeper penetration. This is contrasted with DCEP (Direct Current Electrode Positive), where the electrode is the positive pole and more heat is concentrated on the electrode itself rather than the workpiece. AC current alternates between positive and negative, creating a balance of heat between the electrode and the workpiece, which can be useful but does not maximize penetration like DCEN.
When considering what type of current is used in cars, the answer is c. direct current, as automotive electrical systems are typically designed to run on a constant voltage source, and the flow of electric charge is in one direction.
In summary, direct current refers to systems where the source voltage is constant, while alternating current is characterized by a voltage that varies periodically. Due to the steady flow of charge, DC is effective for consistent energy delivery, such as in automotive applications, whereas AC is commonly used for commercial and residential power distribution.