Question

Of what is the electron source of an electron microscope, the cathode, composed?

A) a tungsten wire filament
B) an iron wire filament
C) a titanium wire filament
D) an iron spike filament
E) a tungsten spike filament

Answer 1

The cathode of an electron microscope is composed of a tungsten wire filament, which is heated to emit electrons that are then used to form high-resolution images.

Step-by-step explanation:

The electron source of an electron microscope, which is the cathode, is composed of A) a tungsten wire filament. This tungsten filament acts as the electron emitter due to its high melting point and its ability to emit electrons when heated, a process known as thermionic emission. In an electron microscope, the electrons emitted from the filament are accelerated and focused to form an image with much higher resolution than is possible with light microscopes.