Answer:
The potential difference between the plates is 
Explanation:
Given that,
Distance = 1.4 mm
Electric field strength 
Let the potential difference is V.
We need to calculate the potential difference between the plates
Using formula of electric field


Where, V = potential
d = distance
Put the value into the formula


Hence, The potential difference between the plates is 
Molly & Caden have a stressed
Frequency= velocity of light/wave length
Fr= 3×10^8/510×10^-9
Frequwency=5.88×10^14 Hz
B)
If it is known that the atomic number is 8, we know that the electrons are also 8. Since the atomic mass (O18) is 18, the neutrons are 18-8=10. Option B is the correct answer.
Hope I helped :)