Two different properties
Magnification
Magnification describes how many times larger an image appears than the object's actual size.
Increasing magnification enlarges an image, but does not necessarily reveal additional detail.
Resolution
Resolution is the ability to distinguish two nearby points as separate.
Higher resolution allows neighbouring structures to remain distinct instead of appearing to merge.
The resolving power of a microscope depends on the wavelength used to form its image.
- Longer wavelengths undergo more diffraction, causing greater overlap between the images of nearby points and lowering resolution.
- Visible light therefore limits how closely spaced two structures can be while still appearing separate.
- Electrons have a much shorter wavelength than visible light, giving electron microscopes substantially greater resolving power.
- Structures below approximately 200 nm cannot be resolved by a light microscope; sufficiently close points appear as a single feature.
Exam Tip: Keep magnification separate from resolution. When explaining why an electron microscope reveals finer structures, credit its greater resolving power rather than merely saying that it magnifies more.