An IGCSE Physics student is set a puzzle by his teacher.
He is given four rods, A, B, C and D, all painted white. He is told that two rods are permanent
magnets, another rod is made of iron and the final rod is made of copper. His teacher asks
him to find out, by experiment, which rod is which.
Fig. 8.1 shows the results the student obtains when he puts the rods next to each other.
Which two rods are magnets? ............................. and .............................