In the figure a potential of +1200V is given to point A and point B is earthed, what is the potential at the point P?

Given circuit can be reduced as follows In series combination charge on each capacitor remain same. So using Q = CV⇒C1V1=C2V2⇒31200−VP=6VP−VB ⇒ 1200−VP=2VP         ∵VB=0 ⇒ 3VP=1200⇒VP=400 volt