We have the next information
E= 6000 N/C
d=0.05m
In order to find the electric potential difference we have the next formula
[tex]\Delta V=Ed[/tex]then we substitute the data given in the formula
[tex]\Delta V=(6000\frac{N}{C})(0.05m)=300\frac{J}{C}=300V[/tex]The electric potential difference between them is 300 V