Ask Your Teacher In Example 24.6, we found that the electric field of a charged disk approaches that of a charged particle for distances y that are large compared to R, the radius of the disk. To see a numerical instance of this, calculate the magnitude of the electric field a distance y = 2.8 m from a disk of radius R = 2.8 cm that has a total charge of 6.5 µC using the exact formula as follows. (Enter your answer to at least one decimal place.)