Pupil sheet · Cells under the microscope
Magnification — questions
Name ______________________ Date ____________
Try every question before you use a nudge. Write in full sentences where you are asked to explain.
1. calculate
A drawing of a cell is 60 mm long. The drawing is magnified ×300. Calculate the actual length of the cell in millimetres.
Actual length: ______________ unit ________
Nudge (only if you are stuck): actual size = image size ÷ magnification. Is your answer smaller than the drawing?
2. calculate
The image of a cell in a photograph is 45 mm wide. The real cell is 0.15 mm wide. Calculate the magnification of the photograph.
Magnification (no unit): ______________ unit ________
Nudge (only if you are stuck): magnification = image size ÷ actual size. Both sizes are already in mm.
3. calculate
A pollen grain is 30 µm wide. Convert this to millimetres.
Width: ______________ unit ________
Nudge (only if you are stuck): 1 mm = 1000 µm. A millimetre is the bigger unit, so you need fewer of them: divide by 1000.
4. calculate
A cheek cell is 0.06 mm across. Convert this to micrometres.
Width: ______________ unit ________
Nudge (only if you are stuck): 1 mm = 1000 µm.
5. calculate
A drawing of a red blood cell is 32 mm across. It is magnified ×4000. Calculate the actual diameter of the cell (a) in millimetres and (b) in micrometres.
(a) Actual diameter in mm: ______________ unit ________
(b) Actual diameter in µm: ______________ unit ________
Nudge (only if you are stuck): (a) Will the real cell be bigger or smaller than the drawing? (b) Is a µm bigger or smaller than a mm?
6. state
Which rearrangement gives the actual size of a specimen?
Circle one answer.
- actual size = image size × magnification
- actual size = image size ÷ magnification
- actual size = magnification ÷ image size
- actual size = image size − magnification
Nudge (only if you are stuck): Start from magnification = image size ÷ actual size.
7. calculate
A photograph of a pollen grain has a scale bar labelled 10 µm. The scale bar is 8 mm long on the photograph, and the pollen grain is 24 mm wide on the photograph. Calculate the actual width of the pollen grain in micrometres.
Actual width: ______________ unit ________
Nudge (only if you are stuck): How many scale bars fit across the grain? Each one stands for 10 µm.