Q1: Which of the following properties of a solid is not dependent on crystal imperfection ?

ANS:C - Melting point

The property of a solid that is not dependent on crystal imperfection is melting point. Crystal imperfections, such as vacancies, dislocations, and grain boundaries, can significantly influence various mechanical, electrical, and thermal properties of solids. However, the melting point of a material primarily depends on its chemical composition and interatomic forces rather than crystal structure or imperfections. Here's a brief explanation of each property listed:

1. Ductility: Ductility, the ability of a material to deform plastically without fracturing, can be affected by crystal imperfections. Dislocations, for example, can enhance ductility by allowing atoms to move more easily under stress.
2. Semiconductivity: The electronic properties of semiconductors, including their conductivity and bandgap, are heavily influenced by crystal imperfections. Defects such as dopants, vacancies, and dislocations can alter the electronic structure and conductivity of semiconductors.
3. Melting Point: The melting point of a material primarily depends on its chemical composition and interatomic forces. Crystal imperfections may affect the melting behavior indirectly by influencing the material's microstructure, but they are not the primary factor determining the melting point.
4. Yield Stress: The yield stress, or the stress at which a material begins to deform plastically, can be influenced by crystal imperfections. Dislocations and grain boundaries play significant roles in determining the yield behavior of materials by affecting their strength and plasticity.