Q: Inserting an extra plane of atoms into a crystal lattice produces what?


Read this paragraph and choose the correct option from the provided answers:

Dislocations, Deformations, and Work Hardening Inserting an extra plane of atoms into a crystal lattice produces an edge dislocation. A familiar example of an edge dislocation occurs when an ear of corn contains an extra row of kernels between the other rows (). An edge dislocation in a crystal causes the planes of atoms in the lattice to deform where the extra plane of atoms begins (). The edge dislocation frequently determines whether the entire solid will deform and fail under stress. Deformation occurs when a dislocation moves through a crystal. To illustrate the process, suppose you have a heavy rug that is lying a few inches off-center on a nonskid pad. To move the rug to its proper place, you could pick up one end and pull it. Because of the large area of contact between the rug and the pad, however, they will probably move as a unit. Alternatively, you could pick up the rug and try to set it back down exactly where you want it, but that requires a great deal of effort (and probably at least one extra person). An easier solution is to create a small wrinkle at one end of the rug (an edge dislocation) and gradually push the wrinkle across, resulting in a net movement of the rug as a whole (part (a) in ). Moving the wrinkle requires only a small amount of energy because only a small part of the rug is actually moving at any one time. Similarly, in a solid, the contacts between layers are broken in only one place at a time, which facilitates the deformation process. Saylor URL: http://www. saylor. org/books.

 Choices:

- spot location

- spot dislocation

- edge location

- edge dislocation


A:
edge dislocation