Consider the classic image problem with a conducting plane and a point charge. After finding out the charge density on the plane we integrate to find out the total charge induced. It comes out to be "-q",where q is the charge outside-
My book says "It comes out to be -q, as you can convince...
I never really understand why we should have a 'unit' for a 'count' i.e. the mole. And what is the need of assigning a separate quantity, the amount of substance... we already have 'mass'; don't we ?
P.S. - I mistyped the topic title... It should be "Amount Of Substance as a quantity"