A cylindrical iron rod 8cm high and 6cm in diameter stands In a cylindrical tin until it's depth is 8cm. How far would the level drop when it's rod is removed

Answer 1

hard to say, since we don't know what the level of the contents is.
But the supposed volume submerged is no more than
v = πr^2 h = 72π cm^3

finding the drop in level would entail knowing the diameter of the enclosing tin.

You do have a way of omitting some critical details, there.