Which material is a single crystal grown by vapor deposition?

• A. Ceramics
• B. Whisker
• C. Glass
• D. Roving

Answer: (B)

A whisker is a type of single crystal that is often produced through a vapor deposition process. This technique involves the deposition of material from a vapor phase onto a substrate, allowing the atoms or molecules to arrange in a highly ordered structure, resulting in the formation of a single crystal. Whiskers are characterized by their long, thin forms and excellent mechanical properties, which make them useful in various applications, including reinforcing materials.

On the other hand, ceramics, glass, and roving do not fit the description of single crystals grown by vapor deposition. Ceramics are typically made through the heating and cooling of non-metallic minerals, forming polycrystalline materials rather than single crystals. Glass is an amorphous solid that lacks a long-range ordered crystalline structure. Roving refers to bundles of fibers, which may be made from various materials, but these fibers themselves are not necessarily single crystals and are not produced through vapor deposition.