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In the experiment used to find Young’s modulus of elasticity, what is observed as the applied load is gradually increased up to the breaking stress?

1. The wire’s cross-sectional area keeps reducing, the wire elongates, and eventually it snaps.
2. The wire’s cross-sectional area keeps reducing and the wire snaps.
3. The wire elongates while its cross-sectional area stays unchanged.
4. The wire’s cross-sectional area stays the same and its length also remains unchanged.

Correct answer: The wire’s cross-sectional area keeps reducing, the wire elongates, and eventually it snaps.

Solution

As the load increases, the wire undergoes plastic deformation, which causes it to elongate and reduce in cross-sectional area until it reaches its breaking point.

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