Some exercises to practice microscope magnifications and conversions

1.
Platon IB Diploma Programme
Biology HL
Exercises on microscope magnification and conversions
1. A student is using an optical microscope to observe a plant cell. He
draws the cell image being 120 mm in length. The eyepiece lens
magnification is 10X and the objective lens magnification is 40X.
Calculate the actual size of the cell.
(Assume that the student is drawing at the same scale with the
magnified image)
3. Calculate the actual size of these Chlorella cells. You should measure
Then prepare a table with the cell number, the image size and the actual
(specimen) size.
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2. Explain what is a scale bar in any microscopic image.
at least five cells. Write a number next to each cell that you measured.

2. 4. If a mitochondrion has a length of 10 µm and a student’s
drawing of the mitochondrion is 20 mm, what is the magnification
of the drawing?
5. Place the following organisms and structures in order of increasing
size. Next to each organism/structure note the corresponding
approximate size.
(a) animal cell, (b) plant cell, (c) thickness of plasma membrane (d) virus,
(e) molecules (f) mitochondrion
6. Calculate the actual size of this organelle which is a ________________
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