A solid spherical conductor of radius $20$ cm has a charge

Q $=25$ nC$.$ A second

spherical conductor, initially uncharged, of radius $12$ cm moves toward the first until they touch and then moves away from it$.$ How much charge is there on the second sphere after the two spheres have been separated?

Select one:

Check

$0$ a$.15$ nC$.$

$0$ b$.2\mathrm{.}1$ nC$.$

$0$ c$.9\mathrm{.}4$ nC$.$

or d$.25$ nC$.$

$.$

e$.$

$3\mathrm{.}9$ nC$.$