Q: Which of the following statements about amorphous solids is incorrect ?

Explanation:

Amorphous Solids

Amorphous solids are materials that do not have a long-range ordered atomic structure, unlike crystalline solids which have a highly organized and repeating arrangement of particles. Let’s examine each statement to identify which one is incorrect:

Option A: They melt over a range of temperature
This statement is correct. Amorphous solids do not have a precise melting point. Instead, they soften gradually over a range of temperatures as the kinetic energy of the particles increases.

Option B: They are anisotropic
This statement is incorrect. Amorphous solids are generally isotropic, meaning their properties are the same in all directions. This isotropy arises because there is no long-range order or directional dependence in the arrangement of their particles.

Option C: There is no orderly arrangement of particles
This statement is correct. In amorphous solids, the particles are arranged randomly without any long-range periodicity, which distinguishes them from crystalline solids.

Option D: They are rigid and incompressible
This statement is correct. Despite the lack of long-range order, amorphous solids maintain a rigid structure and are typically incompressible because the particles are closely packed together.

Therefore, the incorrect statement about amorphous solids is that they are anisotropic.