Is the electric field produced only by charges within the slab, or is the field also due to charges outside the slab? How can you tell?

hello your question is incomplete attached below is the missing figure of the question

The field is due to the charges outside the slab

Explanation:

The Electric field produced is due to the charges outside of the slab and this is due to the fact that the Electric field inside the slab will always be zero

as seen in the fig attached ; given  x = 0 , Ex = 125 N/C

when heated, the valance electrons increased their speed and transferred the heat from electron to electron.   i just took the test.