lesson
Use the same units before dividing
1 · Learn
Magnification equals image size divided by actual size. It is a ratio, so convert both measurements to the same units first. Resolution describes the ability to distinguish close details and is not the same as making an image larger.
An enlarged blurred image can have greater magnification without revealing new detail. State whether a measurement comes from a calibrated scale bar or an assumed display size.
2 · Worked example
An image is 20 mm long and the object 50 micrometres. Converting 20 mm to 20,000 micrometres gives magnification 400.
3 · Your turn
An image is 12 mm and actual size 30 micrometres. Find magnification.
Check your answer
400 times.
4 · Apply your learning
Check an approved scale-bar image and explain why resizing the image changes a printed magnification label but scales the bar with it.
Adult guidance and safety
Use supplied data and approved diagrams. Laboratory work requires qualified supervision, suitable equipment and a risk assessment. No independent chemical, electrical, heating, radiation or biological-culture experiments. Human biology is general education, not personal diagnosis or treatment.
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