What's the effect on the image when you open or close the diaphragm under the microscope?
Biology and microscope :)
When you open or close the diaphragm under the microscope, the image magnification is affected. An image contrast is achieved for it to be seen clearly. This is because the diaphragm has an aperture at its end that affects the light adjustments that bring the image into focus. Read more form http://www.cas.vanderbilt.edu/bsci111a/equipment/compound-microscope/light-microscopy.htm.