Final answer:
The electrical resistance of the skin due to sweating from emotional arousal is measured by a galvanometer, which reflects changes in resistance when the current flows through it.
Step-by-step explanation:
The electrical resistance of the skin associated with sweating that accompanies emotional arousal is measured by a galvanometer. A galvanometer is a device that is used in analog meters, where current flow through the galvanometer results in a proportional needle deflection. This deflection is due to the force of a magnetic field upon a current-carrying wire. In the context of measuring skin resistance, it can detect changes in resistance levels due to sweating, which indicates an emotional or sympathetic nervous system response.