Microscopy

Question 1

Define resolution

Answer 1

the minimum distance a microscope can actually differentiate two points without blurring them together

Question 2

Define resolving power

Answer 2

“specs of a microscope”
- the smallest detail that could technically be seen by microscope

Question 3

As resolving power increase, the VALUE for resolution __

Answer 3

As resolving power increase, the VALUE for resolution DECREASES

NOTE: distance between two objects becomes smaller = resolution “gets better”

Question 4

Calculate total magnification

Answer 4

Ocular lens x objective lens ie. (10X)(50X)= (500X)

Question 5

Calculate empty magnification. What does this mean ?

Answer 5

Empty magnification> 1000xNA

Increased magnification of an object WITHOUT increased resolving power/ detail (when image becomes fuzzy)

Question 6

Calculate resolution

Answer 6

[1.22λ/ NA(obj) + NA(cond)]

[1.22λ/ 2NA(obj)]

Question 7

In a properly configured microscope, NA(obj) + NA(cond) = ?

Answer 7

2NA(obj)

obj= objective lens
cond= condenser

Question 8

Greatest detail (greater resolving power, smaller value for resolution) is seen in shorter or longer wavelengths ?

Answer 8

Shorter wavelengths

Question 9

As Numerical Aperture increases, resolution becomes __ and resolving power __.

Answer 9

As Numerical Aperture increases, resolution becomes A SMALLER NUMBER and resolving power INCREASES

Question 10

Components of a microscope

Question 11

What kind of image is formed by a microscope ?

Answer 11

A VIRTUAL image; object is before the focal point
- stays inverted; not flipped by ocular

Question 12

What is the Numerical Aperture ?

Answer 12

measure of a len’s light-gathering potential
- depends on lens aperture AND refractive index of air/ oil

Question 13

What is the purpose of immersion oil ?

Answer 13

• has a high refractive index
• increases NA and resolving power