The surface charge density of a thin charged disc of radius R is `sigma`. The value of the electric field at the centre of the disc `(sigma)/(2 epsilon_0)` . With respect to the field at the centre, the electric field along the axis at a distance R from the centre of the disc is

Explanation

The electric field strength on the axis at a distance "x" from its centre of uniform charged circular disc is
`E = (sigma)/(2 epsilon_0) (1-(x))/((x^2 + R^2)^(1//2))`. At centre , `E_(0) = (sigma)/(2 epsilon_0)`
At distance `x = R`,
`E = (sigma)/(2 epsilon_0) (0.37) = 0.37 E_0`