This is isn't exactly a problem,but actually something i don't understand in the book i was following, so there this art. about 'Principle of a Generator', whose description is given as, " A generator is an instrument for producing high voltages in the MeV range.
Its design based on the principle that if a charged conductor (labeled A) is brought in contact with a hollow conductor (labeled B), all of its charge transfer to the hollow conductor no matter how high the potential of the later may be.
I have added the supporting equations as attachments (images ).
3. The confusion :
(check all images, mainly the 3 equations in them)
In those attached images, i think the the potential at shell A(1st equation i.e Va =) and B (second equation Vb =) must be the sum of potential due to shell A and B at the required shell (the shell for which we want to find the potential for/at ), so instead of taking difference while calculating the potential at shell A and B, we should simply add them, no ? (Assuming charges are positive or keeping them as variables, there really isn't any reason to assume otherwise ?)
But author has, subtracted charges i.e qa/ra -qb/rb.
I think we should have added them. (i.e qa/ra + qb/rb. )
I hope i'm not too confusing, i'm newbie and don't use internet much.