Lie Detector Machine Identification

This question requires identifying which of the listed devices functions as a lie detector machine.

Device Functions Overview

• Tachometer: Measures the rotational speed of an object, typically in revolutions per minute (RPM).
• Telescope: An optical instrument used to observe remote objects by collecting electromagnetic radiation (like visible light).
• Photometer: Measures the intensity of light by comparing the intensity of light from two different sources.
• Polygraph: A device that monitors and records several physiological variables (such as blood pressure, pulse, respiration, and skin conductivity) while a person is asked and answers questions. It is commonly referred to as a lie detector test.

Identification of Lie Detector

The Polygraph is specifically designed and commonly known for its use in detecting deception by monitoring physiological responses. The other devices serve entirely different scientific and technical purposes.