Q : Adapter charge iPhone and iPad can cross using together?

A : iPhone and iPad mini need only 5w adapter to charged, but for iPad that have bigger diaply than iPad mini it need 10w and 12w adapter to charged, that you can see how many Watt of adapter that screen on. 5w Adapter can use to charge iPhone but may can not use to charge iPad, how ever 10w and 12w adapter can use to charge all both of iPhone and iPad.