Which of the following represents a unit of electrical resistance?

The correct answer is Ohm, which is a unit of electrical resistance in the International System of Units (SI). Electrical resistance measures how much a material opposes the flow of electric current. Understanding ohms is critical in skincare, especially when working with equipment like microcurrent devices and LED therapy, as it affects how these devices operate and interact with the skin.

In more detail, when you have a higher resistance in a circuit (measured in ohms), it implies that less current will flow for a given voltage. This principle is crucial for skincare professionals who need to comprehend how different devices impact the skin’s cells and tissues through electrical stimulation.

The other options represent different electrical concepts: volts measure electrical potential (voltage), watts indicate power consumption (the rate at which energy is used), and amperes measure electric current (the flow of electric charge). Each of these has its importance, but they do not define resistance like ohms do, underscoring why ohms is the correct answer in this context of electrical concepts.