We can check the validity of an equation by using unit analysis of the physical quantities involved in the equation. In the analysis of the unit-wise equation, we check the units of each term involved in the equation. If each term has the same units, the given equation is validated as true, otherwise false.

For example, an equation $\rm v = u + at$ is a valid physical equation. This is because the units of $\rm v$ is $\rm ms^{-1}$, $\rm u$ is $\rm ms^{-1}$, and $\rm at$ is $\rm ms^{-2} \cdot s = ms^{-1}$. Each term has the same units. Hence, the given equation is valid.