Question

The product particles having radius less than critical radius ($r_c$) during nucleation are known as

• A. Nuclei
• B. Embryos
• C. Elements
• D. Atoms

Hint:

Embryos are unstable clusters; only when they exceed the critical radius do they become stable nuclei.

Answer 1

The Correct Option is B

Step 1: Understanding nucleation.
Nucleation is the initial process during a phase transformation where small clusters of atoms form in the parent phase. These clusters may grow or dissolve depending on their size.
Step 2: Concept of critical radius.
There exists a critical radius ($r_c$) during nucleation. Clusters with radius smaller than $r_c$ are unstable and tend to dissolve back into the parent phase.
Step 3: Definition of embryos.
Clusters or particles with radius less than the critical radius are called embryos. Only those clusters that grow beyond the critical radius become stable nuclei.
Step 4: Conclusion.
Hence, product particles having radius less than the critical radius are known as embryos.