To solve this problem, we need to analyze the properties of electromagnetic waves in free space.$\\$Let's examine each option:$\\$• Option 1: They travel with a speed equal to $\frac{1}{\sqrt{\mu_0 \varepsilon_0}}. \\$This is a true statement. The speed of electromagnetic waves in free space is given by $\\ c = \frac{1}{\sqrt{\mu_0 \varepsilon_0}},$ where $\mu_0$ is the permeability and $\varepsilon_0$ is the permittivity of free space.$\\$• Option 2: They originate from charges moving with uniform speed.$\\$This statement is false. Electromagnetic waves are generated by accelerating charges, not charges moving at a uniform speed.$\\$• Option 3: They are transverse in nature.$\\$This is true. Electromagnetic waves are transverse waves, meaning the electric and magnetic fields oscillate perpendicular to the direction of wave propagation.$\\$• Option 4: The energy density in electric field is equal to energy density in magnetic field.$\\$This is true. In an electromagnetic wave, the energy density of the electric field is equal to the energy density of the magnetic field.$\\$Therefore, the property which is NOT of an electromagnetic wave travelling in free space is:$\\$Option 2: They originate from charges moving with uniform speed.$\\$Thus, the correct answer is Option 2.