TeXes Science Practice Test 2025 - Free Science Exam Practice Questions and Study Guide

The equation that represents a physical constant is associated with the relationship between various fundamental constants in physics. In the choice provided, the expression \( \epsilon_0 = \frac{1}{\mu_0 c^2} \) connects the permittivity of free space \( \epsilon_0 \), the permeability of free space \( \mu_0 \), and the speed of light \( c \). This relationship indicates how these constants are intertwined in electromagnetism and is based on the foundations of Maxwell's equations. This expression signifies that \( \epsilon_0 \) is not just a value but is defined through its relationship to other constants, thereby qualifying it as a representation of a physical constant.

The other choices relate to different phenomena or equations in physics but do not solely represent physical constants themselves. For instance, the equation involving \( c^2 \), \( \epsilon_0 \), and \( \mu_0 \) illustrates the interactions of these constants rather than being a standalone constant. Similarly, the equations for velocity and momentum encompass quantities that depend on the specific circumstances of an object's motion but do not describe inherent physical constants. Thus, this makes the equation \( \epsilon_0 = \frac{1}{\mu