Where are the focus controls typically located on a standard compound light microscope?

• A. On the illuminator, below the stage
• B. On the stage, next to the specimen holder
• C. On the eyepiece tube, above the objectives
• D. On the arm of the microscope, near the base

Answer: (D)

Verified step by step guidance

1. Understand the main parts of a standard compound light microscope: the base, arm, stage, illuminator, eyepiece tube, and objectives.
2. Recall that the focus controls are used to adjust the clarity of the image by moving the stage or the objective lenses closer or farther from the specimen.
3. Identify that the coarse and fine focus knobs are typically located on the arm of the microscope, which connects the base to the head (where the eyepiece and objectives are).
4. Note that the illuminator is located below the stage and is used to provide light, not for focusing.
5. Recognize that the stage holds the specimen and the eyepiece tube is above the objectives, but neither contains the focus controls.