The electric field between two parallel plates has a magnitude of 1250 n/c. the positive plate is 0.05 m away from the negative plate. the electric potential difference between the plates, rounded to the tenths place, is v.

In electronics, electric field is simply defined as the electric force per unit charge, or Newton/Coulomb. When you multiply the electric field with the distance between the charged parallel plates, it will yield the voltage. Thus,

E = V*d
1250 N/C = V*0.05 m
V = 25,000 volts

Answer (d) the universe had cooled enough for atoms to combine, protons and neutrons were too far apart to form nuclei;