Sorry if i have posted under the wrong catagorie physics is new to me so im still getting my head around it. Here is the question that is giving me a bit of bother; An airplane is flying through a thunder cloud at an altitude of 2km. If the cloud has a charge concentration of 40C at an altitude of 3km above the ground and -40C at 1km altitude. What is the ambient electric field exsperienced by the air craft? Additional information k = 9 x 10^9 N-m/C^2) so far i have think the equations to be used are F=kQ,Q2 / r^2 this is what i get when i fill the following information = (9*10^9)*(40)*(-40) / 1^2 this equaling -1.44^13 Am i going the right way about it or have i missed a few steps? any guidance would greatly be appreciated.