... preparation process will be explained in detail later in the essay. There are three electromagnetic lenses in a TEM. Electromagnetic lenses are used because firstly electron beams cannot pass through glass, and secondly, as electrons are charged particles, they are affected by a magnetic field. The first is called the condenser. This focuses the electron beam onto the specimen. As the electron beam passes through the specimen, there are 2 further lenses beneath the specimen. The second lens is called the objective. This focuses and magnifies the first image. The degree of magnification is dependent on the applied voltage. The third lens, the projector allows further magnification, and the selection of the area of the image to be viewed. As the path of the electron beam could be impeded by collisions between the electrons and air particles, the electron beam passes through a vacuum. As there is a vacuum, ...

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