Answer
In this question we have given,
Height of plane, h1=2000m
Height at which charge concentration is 40C, h2=3000m
Height at which charge concentration is -40C, h3=1000m
charge concentaration, q1=40C
charge concentaration, q2=-40C
let the charge concentrations at height h2 and h3 as point charges
Now we will first find the electric feild on plane due to positive charge q1=40
![E1= k*q1/(h1-h2)..............(1)](https://tex.z-dn.net/?f=E1%3D%20k%2Aq1%2F%28h1-h2%29..............%281%29)
Here k=8.98755*10^9N.m^2/C^2
q1=40C
put values of k, q1 , h1 and h2 in equation 1
\\
V/m[/tex]
similarly electric feild due to negative charge q2=-40
\\
![E2=359502V/m](https://tex.z-dn.net/?f=E2%3D359502V%2Fm)
Total electric feild E at the aircraft is given as
...............(2)
Put values of E1 and E2 in equation2
![\\E=359502+359502\\E= 719004V/m\\](https://tex.z-dn.net/?f=%5C%5CE%3D359502%2B359502%5C%5CE%3D%20719004V%2Fm%5C%5C)
therefore s Total electric feild E at the aircraft is E= 719004V/m