Electron beams are streams of electrons that are emitted from a source, typically a heated filament or a cathode. These beams are directed and focused using electric and magnetic fields, allowing them to travel in a straight line. Electron beams are commonly used in various applications, including scanning electron microscopy and electron beam lithography, where they help create detailed images or patterns on surfaces. In addition to their use in scientific research, electron beams are also employed in industrial processes, such as electron beam welding and radiation therapy for cancer treatment. The ability to control and manipulate electron beams makes them valuable tools in both technology and medicine.