Chapter 18, Problem 43P

You have a parallel plate capacitor. (a) Determine the average $\stackrel{\to }{E}$ field between the plates if a 120-V potential difference exists across the plates. Their separation is 0.50 cm. (b) A spark will jump if the magnitude of the $\stackrel{\to }{E}$ field exceeds $\text{3}\text{.0 }\times {\text{ 10}}^{\text{6}}\text{V/m}$ when air separates the plates. What is the closest the plates can be placed to each other without sparking?