Microscopes: parts, types and total magnification

Grade 9 Science Worksheet - Building Confidence

Circle the best answer.

1. 1.

   A drawing of a cell is 36 mm long and made at 900×. Ari wants the real cell's length. How long is it?

   • 32,400 µm
   • 40 µm
   • 0.04 µm
   • 400 µm
2. 2.

   A photo shows a cell 60 mm long. Bo knows the real cell is 30 µm long. What is the magnification?

   • 200×
   • 2×
   • 2,000×
   • 1,800,000×

3. Read this first

   Red blood cell on a photo (example data)

   item	length on the photo (mm)	real length (µm)
   scale bar	25	5
   red blood cell	40	?

4. 3.

   Esme uses the photo's scale bar to size a red blood cell. How wide is the real cell?

   • 8 mm
   • 8 µm
   • 200 µm
   • 3.1 µm
5. 4.

   1 µm = 1,000 nm. Kira views a rod-shaped bacterium 0.5 µm long. Can a light microscope show its two ends as separate points?

   • No: 0.5 is smaller than 200, so it is too small
   • Yes: 0.5 µm is 500 nm, which is more than 200 nm
   • An electron microscope could separate them, but a light one could not
   • No, but a stronger eyepiece would separate them

6. Field of view (example data)

   total magnification	field diameter (mm)
   100×	1.8
   400×	0.45

7. 5.

   The field of view is 1.8 mm wide at 100×. Milo switches to 400×. How wide is the field now?

   • 7.2 mm
   • 0.45 mm
   • 0.9 mm
   • 0.045 mm
8. 6.

   1 mm = 1,000 µm. Noah reads that the 400× field is 0.45 mm wide. About how many red blood cells (8 µm) fit side by side across it?

   • About 0.056 cells
   • About 5.6 cells
   • About 56 cells
   • About 3,600 cells
9. 7.

   1 mm = 1,000 µm. A cell spans one fifth of the 0.45 mm field at 400×. How long is Pia's cell?

   • 90 mm
   • 9 µm
   • 90 µm
   • 2,250 µm

10. Two kinds of microscope (real data, from OpenStax Biology 2e)

    microscope	magnification	resolution	living cells?
    light (college lab)	about 400 times	about 200 nanometers	yes
    electron	about 100,000 times	50 picometers	no

    1 nm = 1,000 pm.

11. 8.

    Ren compares resolutions. How many times finer is the electron microscope's resolution than the light microscope's?

    • About 4,000,000 times finer
    • About 4 times finer
    • About 4,000 times finer
    • About 400 times finer
12. 9.

    Two structures are 100 nm apart. Tala wants to see them as two. Which microscope works?

    • An electron microscope, since 50 pm is far finer than 100 nm
    • A light microscope at its highest power
    • A light microscope, because it can look at living cells
    • Either one, since 100 nm is a large gap

13. Two electron microscopes (facts from OpenStax Biology 2e)

    kind	how the beam works	what it shows
    scanning	moves back and forth across the surface	surface details
    transmission	passes through a thin slice	internal structures

14. 10.

    Zee wants to see the inside of a cell's nucleus and mitochondria. Which microscope works?

    • A light microscope, since it shows inside structures finest
    • A scanning electron microscope, since it moves across the specimen
    • A transmission electron microscope, since its beam passes through a thin slice
    • A scanning electron microscope, since electron beams show the inside too