Charge is distributed uniformly on the surface of a large flat plate. the electric field 2 cm from the plate is 30 n/c. the electric field 4 cm from the plate is:

The electric field produced by a large flat plate with uniform charge density on its surface can be found by using Gauss law, and it is equal to

where
is the charge density
is the vacuum permittivity

We see that the intensity of the electric field does not depend on the distance from the plate. Therefore, the strenght of the electric field at 4 cm from the plate is equal to the strength of the electric field at 2 cm from the plate:

The electric field at 4 cm from the plate is will also be 30 N/C because the distance does not affect the intensity of the electric field.

From Gauss law:

For a surface with uniform charge density:

Where

- charge density

-  vacuum permittivity

From the equation, the distance does not affect the intensity of the electric field.  Thus, the electric field 2 cm or 4 cm away from the plate will be equal.

Therefore, the electric field at 4 cm from the plate is will also be 30 N/C.

Learn more about Gauss law,

link

Physical properties are:
-odor
-shape
-texture
-hardness
Texture is the one which is responsible fo how something feels.