3.1: Practice for Microscopy Calculations
- Page ID
- 72646
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The following problems will help you practice calculating total magnification, field diameter, and estimating cell size. Answers are on the last page.
This video will show you how to do the microscopy calculations below: http://youtu.be/H5po6RbFaJs?hd=1
Practice Calculating Total Magnification:
1. Calculate the total magnification of a slide viewed using a 10x ocular lens and a 45x objective lens.
2. Calculate the total magnification of a slide viewed using a 12x ocular lens and a 30x objective lens.
3. Calculate the total magnification of a slide viewed using a 10x ocular lens and a 2x objective lens.
4. Calculate the total magnification of a slide viewed using a 15x ocular lens and a 40x objective lens.
5. Calculate the total magnification of a slide viewed using a 12x ocular lens and a 25x objective lens.
6. Calculate the magnification of the objective lens when using a 12x ocular lens with a total magnification of 480x.
Practice Calculating Field Diameter (use both millimeters and micrometers in your answers):
7. Calculate the field diameter (in millimeters and micrometers) for the 40X objective. You know that the 4x objective has a field diameter of 6mm or 6000 micrometers.
8. Calculate the field diameter (in millimeters and micrometers) for the 10X objective. You know that the 4x objective has a field diameter of 6mm or 6000 micrometers.
9. Calculate the field diameter (in millimeters and micrometers) for the 125X objective. You know that the 100x objective has a field diameter of 0.2mm.
10. Calculate the field diameter (in millimeters and micrometers) for the 4X objective. You know that the 40x objective has a field diameter of 0.3mm.
11. Calculate the field diameter (in millimeters and micrometers) for the 10X objective. You know that the 40x objective has a field diameter of 0.2mm.
12. Calculate the field diameter (in millimeters and micrometers) for the 100X objective. You know that the 10x objective has a field diameter of 2mm
Practice Estimating Cell Size (use both millimeters and micrometers in your answers):
For all of the following questions, assume the following:
- Field diameter for the 4x objective is 5mm
- Field diameter for the 10x objective is 3mm
- Field diameter for the 40x objective is 0.5mm
- Field diameter for the 100x objective is 0.3mm
ANSWERS
Use the formula, TM = (ocular lens magnification)(objective lens magnification)
1. TM = 450x
2. TM = 360x
3. TM = 20x
4. TM = 600x
5. TM = 300x
6. The objective lens used is the 40x
Use the formula, (FDA)(TMA) = (FDB)(TMB) (you can use any variable—the letters in the subscript—in place or A and B)
7. 0.6mm or 600 micrometers
8. 2.4mm or 2400 micrometers
9. 0.16mm or 160 micrometers
10. 3mm or 3000 micrometers
11. 0.8mm or 800 micrometers
12. 0.2mm or 200 micrometers
Use the formula, (Field diameter ÷ # of cells that fit across the field = size per cell or size/cell)
13. 0.5mm / 1.5 cells = 0.25mm/neuron or 250 micrometers/ neuron (I estimated that 1.5 neurons would fit across the field of view)
14. 0.3mm / 3 cells = 0.1mm/cell or 100 micrometers/cell (I estimated that 3 white blood cells would fit across the field of view)
15. 3mm / 60 cells = 0.05mm/cell or 50 micrometers/cell (I estimated that 60 cuboidal cells would fit across the field of view)
16. 5mm / 10 cells = 0.5mm/cell or 500micrometers/cell (I estimated that 10 squamous cells would fit across the field of view)