Question

Scanning electron microscopy is most often used to reveal __________.

1) surface structures.
2) internal structures.
3) both surface and internal structures simultaneously.
4) either surface or internal structures, but not simultaneously.

Answer 1

Scanning electron microscopy (SEM) is primarily used to reveal surface structures of samples, providing three-dimensional, high-resolution images.

Step-by-step explanation:

Scanning electron microscopy (SEM) is most often used to reveal surface structures. SEM creates detailed images by using a beam of electrons that interacts with the sample's surface, primarily from secondary electrons that are ejected from the surface. This method can yield detailed, three-dimensional images that are viewed on a monitor, providing valuable insights into the surface characteristics of various biological materials, such as the external texture of a pollen grain.

Specimens for SEM analysis are usually prepared by drying and fixing, followed by a coating of a thin metal layer, often gold, to enhance the electron signal. While transmission electron microscopy (TEM) is essential for examining internal structures like organelles within a cell, SEM is particularly adept at showing the complexities of surface textures at high magnifications. However, SEM does not reveal the internal composition of objects, which is the domain of TEM.