The unit used to measure opposition to current flow is known as:

The unit used to measure opposition to current flow is the Ohm. This unit is a fundamental aspect of electrical engineering, defined by Ohm’s Law, which relates voltage, current, and resistance. Specifically, one Ohm is defined as the amount of resistance that allows one ampere of current to flow when one volt of electrical potential is applied.

This concept of resistance is crucial for understanding how electrical circuits operate. When current flows through a conductor, it encounters resistance, which can be due to the material of the conductor, its temperature, and its dimensions. By measuring resistance in Ohms, engineers can design and analyze circuits effectively to ensure they function correctly and safely.

In the context of the other units mentioned: Joules is a measurement of energy, Hertz measures frequency, and Newton quantifies force. While each of these units is essential in their respective fields of physics and engineering, they do not relate to measuring opposition to current flow, which is why the Ohm is the correct choice.