Ontario Grade 9 Destreamed Science (SNC1W1) 2026 Practice Exam

The unit used to measure electrical resistance is ohms. Resistance is a property of a material or component that opposes the flow of electric current. It is represented by the Greek letter omega (Ω). This relationship is defined by Ohm's Law, which states that the voltage (in volts) across a conductor is proportional to the current (in amperes) flowing through it, with resistance (in ohms) being the proportionality factor.

Understanding resistance is essential for analyzing electrical circuits, as it helps determine how much current will flow in response to a given voltage. This concept is fundamental in the design and functioning of electrical devices. Other units related to electricity, like volts (which measure electric potential), amperes (which measure current flow), and watts (which measure power), serve different purposes but do not quantify resistance itself.