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A wire of length L is hanging from a fixed support. The length changes to L1 and L2 when masses 1 kg and 2 kg are suspended respectively from its free end. Then the value of L is equal to -

1. √(L1 L2)
2. (L1 + L2)/2
3. 2L1 - L2
4. 3L1 - 2L2

Correct answer: 2L1 - L2

Solution

The correct option, 2L1 - L2, is derived from the relationship between the elongation of the wire under different loads. When the first mass is added, the wire stretches to L1, and when the second mass is added, it stretches to L2. The difference in elongation allows us to express the original length L in terms of L1 and L2.

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