Biology 3.1 Investigating the Structure of Cells

Light microscope - relatively long wavelength of light rays means can only distinguish between objects 0.2micrometre's apart.

Using beams of electrons = shorter wavelengths, can distinguish between objects as 0.1nm apart.

• km = kilometre = 1000 metres
• micrometre = um = 10-6 metres
• nanometre = nm = 10-9 metres

Magnification and Resolution

Material put under microscope = object.

Magnification = size of image/size of object 

Size of image = magnification x size of object.

Sizes need to be in the same unit - may have to convert units.

NB: Light has longer wavelength than beam of electrons, not light microscope has longer wavelength than electron microscope.

Resolution = minimum distance apart two objects can be in order to appear as seperate items.

Resolving power depends on the wavelength or form of radiation used.

Greater resolution…