Answer:
c) E/2
Explanation:
The relationship between magnitude of electric field (E), distance between the plates (d) and voltage across the plates (V), for a uniform electric field, is given by:
[tex]V=Ed[/tex]
Re-arranging it, we can write it as
[tex]E=\frac{V}{d}[/tex]
in the problem, the potential across the plates is kept constant: V' = V.
However, the distance between the plates is doubled: d' = 2d
Therefore, we can calculate the new magnitude of the electric field:
[tex]E'=\frac{V'}{d'}=\frac{V}{2d}=\frac{1}{2}\frac{V}{d}=\frac{E}{2}[/tex]
So the correct answer is
c)E/2