What is the unit of measure for frequency in the International System of Units (SI)?

The unit of measure for frequency in the International System of Units (SI) is Hertz (Hz). Frequency represents the number of cycles or events that occur in a unit of time, specifically one second. Thus, one Hertz indicates one cycle per second. This unit is crucial in various fields such as physics, engineering, and telecommunications, where understanding the rate at which events occur is essential.

Other options are units associated with different physical quantities: Joules measure energy, Newtons measure force, and Pascals measure pressure. Each of these plays a unique role in physical science, but they do not measure frequency. Hertz specifically relates to the concept of periodicity and oscillation, making it the appropriate and correct answer for frequency measurement in the SI system.