Which part of a microscope controls the amount of light reaching the object?
There are several components to a microscope. Starting at the bottom, there is the base, which is what supports the entire microscope. Usually the light source is attached to the base. The light source can be either a mirror or lightbulb/lamp. The arm attaches the base and the head portion. The ocular or eyepiece is the portion that one looks through to see the specimen. This usually contains a 10x magnification. The ocular is connected to the body tube, which connects to the revolving nose piece, which contains the objectives. The objectives magnify the specimen, at varying degrees, on a slide which sits on the stage. The slide is held in place on the stage by clips. There are two adjustments that clarify the image of the specimen. The coarse adjustment visible moves the stage to do major focus adjustments and the fine adjustment does minor moves to fine-tune the image. Finally, the diaphragm is located under the stage and determines the amount of light that is able to pass through the specimen.