# Physics

posted by
**Valerie**
.

As a crude model for lightning, consider the ground to be one plate of a parallel-plate capacitor and a cloud at an altitude of 590 m to be the other plate. Assume the surface area of the cloud to be the same as the area of a square that is 0.50 km on a side.

(a) What is the capacitance of this capacitor?

(b) How much charge can the cloud hold before the dielectric strength of the air is exceeded and a spark (lightning) results?

for a I tried using c = Eo * A / d, but it didn't come out right. can someone help?