Reshma can identify the two magnets by bringing one metal bar close to the other two. If one bar repels either of the remaining two, it’s a magnet, and the bar it repels is also a magnet. The bar that only attracts but doesn’t repel is the piece of iron.
Here’s a step-by-step explanation:
Test one bar against the others: Bring one of the bars close to each of the other two.
Observe for repulsion: If one of the bars repels another, it means both those bars are magnets.
Identify the iron: The bar that attracts but doesn’t repel any of the others is the piece of iron.
Example:
If bar A repels bar B, then both bar A and bar B are magnets.
If bar C attracts both bar A and bar B but doesn’t repel either of them, then bar C is the piece of iron.