Microscope in poor lighting conditions with a purple light field of view will be clearer Why?

It is because the resolution of a microscope is inversely related to the wavelength of its light source. The shorter the wavelength, the higher the resolution of the microscope. The wavelength of violet light is small compared to visible light, so if you use the smaller ultraviolet light as the light source of the microscope, its resolution will be higher than the visible light source microscope (0.2 microns) double. This is why electron microscopes have millions of times magnification and nanometer resolution (the wavelength of the electron stream is about 0.03 angstroms).