Magnification and specimen size

1. Which expression correctly defines magnification when image size and actual size are corresponding lengths in the same unit?

1. image size ÷ actual size
2. actual size ÷ image size
3. image size × actual size
4. image size − actual size

2. Convert an actual specimen length of 0.38 mm to micrometres. No magnification calculation is required.

1. 0.00038 μm
2. 38 μm
3. 380 μm
4. 3800 μm

3. Convert an actual specimen length of 460 μm to millimetres. No image resizing is involved.

1. 4.6 mm
2. 0.46 mm
3. 46 mm
4. 0.046 mm

4. An unresized image has a corresponding specimen length of 60 mm at ×150. What is the actual length in millimetres?

1. 9000 mm
2. 2.5 mm
3. 0.04 mm
4. 0.4 mm

5. A specimen is actually 0.08 mm long and its corresponding length is 32 mm in an unresized image. What is the magnification?

1. ×400
2. ×40
3. ×4
4. ×2500

6. A specimen is actually 25 μm long and has a stated image length of 15 mm. The image is unresized. What is its magnification?

1. ×60
2. ×375
3. ×600
4. ×6000

7. A specimen is actually 0.12 mm wide and is represented at ×250. The image is not resized. What is the corresponding image width?

1. 2.08 mm
2. 30 mm
3. 0.00048 mm
4. 120 mm

8. An unresized image length is 84 mm and the corresponding actual specimen length is 70 μm. What is the magnification?

1. ×12
2. ×120
3. ×840
4. ×1200

9. A scale bar measures 12 mm on an unresized image and represents an actual distance of 30 μm. What is the image magnification? All needed measurements are stated here.

1. ×400
2. ×40
3. ×250
4. ×360

10. A corresponding length is stated as 45 mm in an unresized image at ×900. What is the actual specimen length in micrometres?

1. 5 μm
2. 40500 μm
3. 50 μm
4. 500 μm

11. An unresized image length is 2.4 mm and the corresponding actual length is 40 μm. What is the magnification?

1. ×6
2. ×60
3. ×96
4. ×600

12. A specimen is actually 6 μm long and is represented at ×2500 without later resizing. What is the image length in millimetres?

1. 0.0024 mm
2. 1.5 mm
3. 150 mm
4. 15 mm

13. Specimen A has image length 36 mm at ×600. Specimen B has image length 20 mm at ×250. Both images are unresized and each length covers the whole corresponding specimen. Which specimen is actually longer?

1. Specimen B
2. Specimen A
3. They have equal actual lengths
4. There is insufficient information

14. Convert an actual width of 0.0075 mm to micrometres before using it in a calculation.

1. 0.75 μm
2. 75 μm
3. 7.5 μm
4. 7500 μm

15. Convert an actual length of 1250 μm to millimetres before comparing it with an image measurement.

1. 0.125 mm
2. 1.25 mm
3. 12.5 mm
4. 125 mm

16. An unresized image length is 9 mm and the corresponding actual length is 3 μm. What is the magnification?

1. ×3
2. ×30
3. ×300
4. ×3000

17. An unresized image shows a corresponding length of 48 mm for a specimen that is actually 0.16 mm long. What is the magnification?

1. ×300
2. ×30
3. ×768
4. ×0.0033

18. An original image at ×800 has a stated length of 20 mm. It is enlarged uniformly so all linear image lengths become 1.5 times as long; the specimen is unchanged. What is the new magnification?

1. ×533
2. ×800
3. ×1200
4. ×1800

19. A corresponding image length is 72 mm at ×240, with no later resizing. What is the actual length in micrometres?

1. 30 μm
2. 300 μm
3. 17280 μm
4. 3 μm

20. A scale bar measures 5 mm on an unresized image and represents 2 μm actually. What is the magnification? The bar measurements are fully stated.

1. ×2.5
2. ×250
3. ×1000
4. ×2500

21. A specimen is actually 14 μm long and is represented at ×500 without resizing. What is the corresponding image length in millimetres?

1. 7 mm
2. 0.028 mm
3. 28 mm
4. 7000 mm

22. An unresized image length is 27 mm at ×90. What is the corresponding actual length in micrometres?

1. 3 μm
2. 30 μm
3. 300 μm
4. 2430 μm

23. Which rearrangement finds actual size from a stated image size and magnification, provided the image and actual lengths use compatible units?

1. actual size = magnification ÷ image size
2. actual size = image size ÷ magnification
3. actual size = image size × magnification
4. actual size = image size + magnification

24. Why must image size and actual size be converted to the same length unit before magnification is calculated?

1. So the actual specimen becomes larger
2. So magnification can be reported in millimetres
3. So every answer becomes a whole number
4. So the equal length units cancel and the numerical ratio is valid