Microscopes

Question 1

What is resolution and why is it better in Electron |Microscopes than in light

Answer 1

Ability to distinguish points (close together), Electrons have a shorter wavelength;

Question 2

Scientists use optical microscopes and transmission electron microscopes (TEMs) to investigate cell structure. Explain the advantages and the limitations of using a TEM to investigate cell structure.

Answer 2

Advantages:
1 Small object can be seen;
2 TEM has high resolution;
3 Wavelength of electrons shorter;

Limitations:
4 Cannot look at living cells;
5 Must be in a vacuum;
6 Must cut section / thin specimen;
7 Preparation may create artefact
8 Does not produce colour image;

Question 3

Measuring the size of an object under a microscope

Answer 3

Measure with an eyepiece graticule
Calibrate with the stage micrometer (an object of a known size)
Repeat and calculate an average