Why can an electron microscope have greater magnification than an ordinary microscope?

An electron microscope is an example where wave and particle nature of an electron can be observed.

An ordinary microscope uses the wavelength from visible spectrum while an electron microscope used the wavelength from x-ray spectrum which are shorter and more energetic.

An electron can have larger momentum due to its smaller mass. According to de Broglie wavelength, it also has a very short wavelength due to which it can be used for probing very small sized objects. The wavelength of electron is thousand times smaller than wavelength of visible light. That is why electron microscope have greater magnification than an ordinary microscope.

Since the wavelength of an electron is very small, it carries a large amount of energy with it due to which it might damage the objects its been imposed with.