Study guide for Microscopes
Define magnification and resolution in words.
Microscopes must do two things:
- Magnification = make things appear bigger
- Resolution = ability to see two items that are close together as two separate individual objects
Calculate the total magnification given the scenarios below:
Oculars 10X; Objectives 4X Total magnification = 40x
Oculars 10X; Objectives 10X Total magnification = 100x
Oculars 10X; Objectives 40X Total magnification = 400x
Oculars 10X; Objectives 100X Total magnification =1000x
Oculars 15X; Objectives 10X Total magnification = 1500x
Oculars 20X; Objectives 4X Total magnification = 80x
Define resolution using a mathematical equation.
Resolving power = (wavelength nM) / 2 * numerical aperture
—> the smaller the wavelength, the better ; the higher the NA, the better
Calculate the resolution of a microscope using light at a wavelength of 400 nM and an objective with a
NA of 2.
RP = (400 nM) / 2 * 2 —> 100
Calculate the resolution of a microscope using light at a wavelength of 600 nM and an objective with a
NA of 0.5.
RP = (600 nM) / 2* 0.5 —> 600
We use a compound, binocular, bright-field light microscope in the Bio 175 lab. What the heck does this
mean?
- Light microscope = uses light to create an image
- Compound = ocular lens + objective lens
- Binocular = two ocular lenses
- Bright-field = sample will absorb some of the light and specimen will appear darker than the surrounding
bright field
What are the basic pieces and parts of a microscope? What are their functions?
- Ocular lenses = lenses you look through, 10x magnification power
- Revolving nosepiece (Turret) = holds the objective lenses and can be rotated to view specimen from different
Define magnification and resolution in words.
Microscopes must do two things:
- Magnification = make things appear bigger
- Resolution = ability to see two items that are close together as two separate individual objects
Calculate the total magnification given the scenarios below:
Oculars 10X; Objectives 4X Total magnification = 40x
Oculars 10X; Objectives 10X Total magnification = 100x
Oculars 10X; Objectives 40X Total magnification = 400x
Oculars 10X; Objectives 100X Total magnification =1000x
Oculars 15X; Objectives 10X Total magnification = 1500x
Oculars 20X; Objectives 4X Total magnification = 80x
Define resolution using a mathematical equation.
Resolving power = (wavelength nM) / 2 * numerical aperture
—> the smaller the wavelength, the better ; the higher the NA, the better
Calculate the resolution of a microscope using light at a wavelength of 400 nM and an objective with a
NA of 2.
RP = (400 nM) / 2 * 2 —> 100
Calculate the resolution of a microscope using light at a wavelength of 600 nM and an objective with a
NA of 0.5.
RP = (600 nM) / 2* 0.5 —> 600
We use a compound, binocular, bright-field light microscope in the Bio 175 lab. What the heck does this
mean?
- Light microscope = uses light to create an image
- Compound = ocular lens + objective lens
- Binocular = two ocular lenses
- Bright-field = sample will absorb some of the light and specimen will appear darker than the surrounding
bright field
What are the basic pieces and parts of a microscope? What are their functions?
- Ocular lenses = lenses you look through, 10x magnification power
- Revolving nosepiece (Turret) = holds the objective lenses and can be rotated to view specimen from different
