4.
GO
Four identical metal spheres have charges of $q_A = -8.0 \mu C$,
$q_B = -2.0 \mu C$, $q_C = +5.0 \mu C$, and $q_D = +12.0 \mu C$. (a) Two of the
spheres are brought together so they touch, and then they are separated.
Which spheres are they, if the final charge on each one is $+5.0 \mu C$?
(b) In a similar manner, which three spheres are brought together and
then separated, if the final charge on each of the three is $+3.0 \mu C$?
(c) The final charge on each of the three separated spheres in part (b) is
$+3.0 \mu C$. How many electrons would have to be added to one of these
spheres to make it electrically neutral?
