What happens when the coarse control knob is rotated at 10X?

When the coarse control knob is rotated at 10X magnification, it allows for significant vertical movement of the stage or the objective lens, facilitating the initial focusing of the specimen. This movement is typically more pronounced than at lower magnifications, enabling the user to quickly bring the specimen into view. However, care must be taken to avoid crashing the lens into the slide, as the working distance is smaller at higher magnifications. After achieving a general focus, fine adjustments can be made with the fine focus knob for clearer viewing.