Final answer:
The worst resolution in a light microscope would come from using a lens with a smaller numerical aperture, as it would be unable to gather sufficient light to resolve fine details clearly.
Step-by-step explanation:
The resolution of a light microscope could be negatively affected by a smaller numerical aperture (NA). The resolution refers to the ability of the microscope to distinguish two points as being separate, and the numerical aperture is directly related to this ability. A lens with a larger NA will have a higher resolving power because it gathers more light, which means that more information is collected to form a clear image. On the other hand, a lens with a smaller NA will result in a lower resolving power. In addition, shorter wavelengths of light are better for resolution as they can resolve finer details. Therefore, higher magnification and shorter wavelength are beneficial for resolution, whereas a smaller numerical aperture would result in the worst resolution in a light microscope.