Answer:
![q'=9.735* 10^(-13)\ C/m^3](https://img.qammunity.org/2020/formulas/physics/high-school/aia4rwtj26zhrz56li5ny2qptbmn6xc6ad.png)
Step-by-step explanation:
Given that
219 m above the ground, the electric field is 141 N/C directed downward.
At 319 m above the ground, the electric field is 103 N/C downward.
If filed is going in to the region then it taken as negative and If filed is going out to the region then it taken as positive.
So net flux = 114 A - 103 A
Net flux= 11 A
Now from Gauss law
![Net\ flux=(q)/(\varepsilon )](https://img.qammunity.org/2020/formulas/physics/high-school/btbugl53kbrodysj1sjgx7p0ma5ruync5t.png)
![\varepsilon =8.85* 10^(-12)](https://img.qammunity.org/2020/formulas/physics/high-school/k980wdvgs6hzdmm504hm036n2o85ywmt35.png)
![11\ A=(q)/(\varepsilon )](https://img.qammunity.org/2020/formulas/physics/high-school/9p9ixjpffrq4lysvoruvqpq09fwrlb7rhn.png)
q= 11 A ε
The average volume charge density(q') is the ratio of charge to the volume.
Volume = A .h
h= 319 - 219
h= 100 m
![q'= (11\ A\ \varepsilon )/( A\ h)](https://img.qammunity.org/2020/formulas/physics/high-school/hr8gu7hscogfnqgteocrcr3l96uk3hfame.png)
![q'= (11\ \varepsilon )/(h)](https://img.qammunity.org/2020/formulas/physics/high-school/nbpo3mrjoh9wjigffbd3yhtn4lspdc9hqj.png)
![q'= (11* 8.85* 10^(-12))/(100)\ C/m^3](https://img.qammunity.org/2020/formulas/physics/high-school/axtsm7sqpn032wu6poevj72865a5d20ssi.png)
![q'=9.735* 10^(-13)\ C/m^3](https://img.qammunity.org/2020/formulas/physics/high-school/aia4rwtj26zhrz56li5ny2qptbmn6xc6ad.png)
So the charge per volume is
![q'=9.735* 10^(-13)\ C/m^3](https://img.qammunity.org/2020/formulas/physics/high-school/aia4rwtj26zhrz56li5ny2qptbmn6xc6ad.png)