Exercise 5: Microscopy

Question 1

Condenser

Answer 1

collect the light rays emitted by its source and direct it to the specimen

Question 2

Numerical Aperture

Answer 2

a measure of its ability to gather light and resolve details of the specimen at a fixed length

Question 3

Limit of resolution (D)

Answer 3

a microscope is the minimum distance between two objects where they can be seen as two separate entities
-short wave lengths filters can decrease D.

Question 4

Total Magnification

Answer 4

calculated by multiplying the power of the OBJECTIVE LENS x power of the OCULAR LENS (10x)

Question 5

Bright-Field Microscopy

Answer 5

• visible light is used
• contrast between the specimen and the background enables the clarity of the picture
• staining improves contrast

Question 6

Phase-Contrast Microscopy

Answer 6

• designed to create a phase shift in light

- useful for live specimens because staining is not necessary

Question 7

Dark-Field Microscopy

Answer 7

• scattered light from the specimen reaches the objective lens forming images of light objects in dark backgrounds
• resolution is better

Question 8

Fluorescence Microscopy

Answer 8

• fluorescent dyes are used

- dyes absorb light of one wavelength and emit light at another wavelength

Question 9

Differential Interference Contrast (DIC) Microscopy

Answer 9

• works best for live specimens because this type of microscope allows the clear visualization of the internal structures
• does not require staining