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The Eyepiece Graticule

The eyepiece graticule and stage micrometer are used to measure the actual size of specimens.The eyepiece graticule is a glass disc marked with 100 divisions.

For example, if forty divisions of the eyepiece correspond to 15micrometers then each eyepiece division is 0.375micrometers.The micrometer stage slide is removed and the specimen slide placed on the stage. The size of the specimen can be determined by measuring it with the eyepiece.

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Specification: OCR Biology A (H020), AS-level, 2.1.1 Cell structure. Topic: Components of Living Systems.

Key terms in this lesson

stage micrometer
A microscope slide bearing a scale of known, precise dimensions, used to calibrate the eyepiece graticule so it can measure real specimen sizes.

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