Question

6. Consider the Earth and a cloud layer 700 m above the planet to be the plates of a parallel - plate capacitor. (a) If the cloud layer has an area of 3.0 km^2 = 3000000 m^2, what is the capacitance?(b) If an electric field strength greater than 3.0 . 10^6 N/C causes the air to break down and conduct charge (lightning), what is the maximum charge the cloud can hold?7. Given a 2.75 muF capacitor, a 3.75 muF capacitor, and a 8.50 V battery, find the charge on each capacitor if you connect them in the following ways. (a) in series across the battery (b) in parallel across the battery

Answer 1

a)

distance , d = 700 m

capacitace , C = epsilon*A/d

C = 8.854 *10^12 * 3 *10^6/(700)

C = 3.79 *10^-8 F

the capacitance is 3.79 *10^-8 F

b)

maximum charge = C * E * d

maximum charge = 3.79 *10^-8 * 3 *10^6 * 700

maximum charge = 79.7 C

the maximum charge the cloud can hold is 79.7 C