COMEDK2015PhysicsMechanical Properties of Solids
The dimensions of four wires of the same material are given below. In which wire the increase in length will be maximum when the same tension is applied?
Options
- ALength 100 ~cm , diameter 1 ~mm
- BLength 200 ~cm , diameter 2 ~mm
- CLength 300 ~cm , diameter 3 ~mm
- DLength 50 ~cm , diameter 0.5 ~mm
Correct answer
D. Length 50 ~cm , diameter 0.5 ~mm
Step-by-step solution
We know that, Young's modulus of elasticity, array ll & Y= F L r² l [where, l is change in length] & l= F L r² Y & l L r² L d² [where, d= diameter] & l L d² array Among the given options, L d² is maximum for the values of L=50 ~cm and d=0.5 ~mm .