# Homework Help: Capacitance of a landing plane in a thunderstorm

1. Apr 20, 2010

### sethman737

1. The problem statement, all variables and given/known data

An airplane flies through a thundercloud and picks up an excess charge of 1 microcoulomb. When the plane comes in to land, its wings form approximately a parallel plate capacitor with the ground. What is the capacitance of this system?
What is the potential of the plane?
Why does this matter and what precautions are taken to avoid this?

2. Relevant equations
C= |Q/V|
V= -Ed (E being determined from Gauss' law)
I would insert the other equations but I'm just learning how to use this system and don't know how to insert the symbols.

3. The attempt at a solution
I am stuck at these equations because I don't know how to find the area of the wings or the distance between the wings and the ground (no dimensions were given for either). Furthermore I don't know if I even need to use these values at all since I may well be using the wrong equations.

2. Apr 20, 2010

### kuruman

The area of the wings depends on the plane. Make a reasonable assumption or visit the web and look up plane specs. Your equations look correct, but you will also need the equation that gives the capacitance of a parallel plate capacitor.