A sphere of radius a=6cm carries a uniform charge density ρ=450nC/m^3.
a) what is the total charge Q of the sphere.
b) Using Gauss's law find the electrical feld inside the sphere at a distance r=2cm from the center of the sphere.
c) Using Gauss's law find the electrical field outside the sphere at a distance r=10cm from the center of the sphere.
d) repeat calculation assusming that the charge Q (calculated in a) is in a point at the center of the sphere. Comment on the difference, if any, between these two values.