Four identical iron bars were dipped in a heap of iron filings one by one. The figure shows the number of iron filings sticking to each of them. Which of the iron bars is not a magnet? Justify your answer.
Step 1: Properties of magnet
Step 2: Analyzing the given figure
As it is clearly visible that iron bar (b) doesn't attract any iron fillings.
Hence, iron bar (b) is not the magnet.