SBI 3U
Mrs. Holterman
Name: _________________________
Date: _________________________
Magnification Problems
Field Diameter on drawing =
40x . x
Magnification
of drawing
F.D.(40x)
Width of specimen = Field diameter on drawing
Width Fit number
Length of specimen = Field diameter on drawing
Length Fit number
Answer each of the following questions on a separate sheet of paper. Show your work!
1. a) What is the field diameter of the low power (40x) of the microscope in the diagram showing a
ruler in the field of view (shown here)?
b) Use the correct equation to find the field diameter at 100x magnification.
2. a) What is the fit number for length and width of the specimen shown below?
b) If the field diameter is 0.45 mm, what is the estimated length and width of this specimen?
3. a) Field diameter (low) = 4.7 mm
Magnification (low) = 40x
Magnification (medium) = 100x
What is the field diameter at medium magnification?
b) What is the field diameter of the microscope in (a) at high magnification (400x)?
4. a) A cork cell was examined under the highest power lens of a microscope, so the overall
magnification is 400x. If the field diameter of this microscope was 4.2mm at 40x, what is the
field of view at 400x?
b) The round cell fits across the field of view 8 times. What is the estimated size of the cell?
c) Often, at this size, measurements are made in micrometers (μm). 1000μm =1mm How long is
the cork cell in μm?
5. A student is studying banana cells using a compound microscope at a magnification of 100x. The
field diameter at 100x is 1.6mm. She estimates that 5 cells could fit lengthwise across the field of
view, and 2 cells could fit across for width. What is the estimated length and width of the banana
cell?
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