Which type of sensor is commonly used for detecting objects without physical contact?

The choice of a proximity sensor as the correct answer makes sense due to its primary function, which is to detect the presence or absence of an object without requiring physical contact. Proximity sensors utilize various methods, such as electromagnetic fields, infrared light, or ultrasonic sound waves, to sense nearby objects. This capability is particularly valuable in applications where contact with an object may lead to wear, contamination, or safety issues.

For instance, in automation and robotics, proximity sensors enable machines to identify the position of objects on a production line without interrupting the workflow or risking damage. Their application in safety systems, such as ensuring safe distances between moving parts, further highlights their importance in modern technology.