Two identical looking iron bars A and B are given, one of which is definitely known to be magnetised (We do not know which one). How would one ascertain whether or not both are magnetised ? If only one is magnetised, how does one ascertain which one ? [Use nothing else but the two bars A and B]

Explanation

Bring different ends of two bars A and B closer. If in some situation repulsive force is experienced then both bars are magnets. However, if force is attractive every time then only one bar is magnetised.
If only one bar is magnetised then take a bar (say A) and bring its one end first on one end of other rod B and then on the middle of rod B. If bar A does not experience any force in the middle of B, it means that B is magnetised but A is non-magnetised. However, if there is no change in force at the end or on the middle then A is magnetised and bar B is non-magnetised.