Two identical looking iron bars A and B are given, one of which definitely known to be magnetised. 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.

If A and B are two events, the probability that exactly one of them occurs is given by

Three identical bar magnets are rivetted together at centre in the same plane as shown in Fig. EP 5.17 (a). This system is placed at rest in a slowly varying magnetic field. It is found that the system of magnets does not show any motion. The north-south poles of one magnet is shown in the Fig. Determine the poles of the remaining two.

Two identical thin bar magnets, each of length L and pole strength m are placed at right angles to each other, with the N pole of one touching the S-pole of the other. Find the magnetic moment of the system.

Two identical solid balls, one of ivory and the other of wet-clay, are dropped form the same height on the flor. Which one will rise to a greater height after striking the floor and why?

Two persons could fit new windows in a house in 3 days : One of the persons fell ill before the work started. How long would the job take now?

A and B are two protons placed in uniform electric field between two parallel plates. Which one will experience greater force?