Question

Why is a uniform layer of carbon applied to a replica after the metal has coated the

specimen at an angle?
A) to make the replica smooth
B) to cement the patches of metal into a solid surface
C) to make the replica rough
D) to make the replica transparent to electrons
E) to make the replica opaque to electrons

Answer 1

The uniform layer of carbon applied after metal coating makes the replica opaque to electrons, enhancing contrast for better image quality in electron microscopy.

Step-by-step explanation:

The process of applying a uniform layer of carbon to a replica after the metal has coated the specimen at an angle is crucial for electron microscopy. This carbon layer is intended to make the replica opaque to electrons, which enhances contrast and allows for the production of a clearer image when examined under a transmission electron microscope (TEM). The carbon acts as a support to the metal, ensuring the replica's stability and electron opacity. Without this layer, parts of the specimen might be transparent to electrons, leading to a lack of contrast and a poor-quality image.