Question

Two wire A and B have equal lengths and are made of the same material, but the diameter of A is twice that of wire B.

• A. Young's modulus of A is twice that of B
• B. Young's modulus is the same for both A and B
• C. A can withstand a greater load before breaking than B
• D. A and B will withstand the same load before breaking

Answer 1

Answer: (B), (C)

Young's modulus is the same for both A and B
A can withstand a greater load before breaking than B

Young's modulus, being an internal property of materials, is independent of shape and size. Thus it will be equal for the same material wires.
The maximum load taken depends on the highest point on stress-strain curve. Since 2 same material wires will have same curve, thus ultimate stress is also same for both.