# 1) As a crude model for lightning, consider the ground to be one plate of a…

1) 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

620 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 0.55 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?

2) An electronic flash unit for a camera contains a capacitor

with a capacitance of 760