$4.$ Consider the scanning transmission electron micrograph $($TEM$)$ of steel given below. The Burgers vectors are indicated by the orange vectors drawn onto this micrograph.

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$\backslash$stackrel$\{\backslash$rightharpoonup$\}\{\backslash$mathrm$\{$h$\}\}$

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A$)$ What are the lines in the micrograph above? Briefly explain these defects are and how they are created.

B$)$ What type of dislocation exists at a$?$

C$)$ What is a Burger's Vector? Briefly explain the significance of a Burger's vector.