Question 1
Which formula is used to calculate magnification?
- actual size ÷ image size
- image size × actual size
- image size − actual size
- image size ÷ actual size
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Answer: D (1)
Question 2
A drawing of a root hair cell is 48 mm long. The actual length of the cell is 0.24 mm. Calculate the magnification of the drawing.
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- 48 ÷ 0.24 (1)
- × 200 (1) correct answer with no working gets 2 marks; ignore × sign; reject units (e.g. 200 mm)
Question 3
A photograph of a cell has a magnification of × 800. The cell in the photograph is 24 mm wide. Calculate the actual width of the cell in mm. Show your working.
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- actual size = image size ÷ magnification (1)
- 24 ÷ 800 (1)
- 0.03 mm (1) correct answer with no working gets 3 marks
Question 4
Supplement (what this means)
Supplement: only for the Extended papers (2 and 4). Core students can skip it. What the labels mean(a) Convert 0.08 mm into µm. [1] (b) A student measures a nucleus in a drawing as 12 mm. The actual width of the nucleus is 6 µm. Calculate the magnification of the drawing. [3]
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- (a) 80 µm (1)
- (b) convert 12 mm to 12 000 µm, or 6 µm to 0.006 mm (1)
- 12 000 ÷ 6 or 12 ÷ 0.006 (1)
- × 2000 (1) correct answer with no working gets 3 marks; reject units
Question 5
The image of a cell is 60 mm wide. The magnification is × 200. What is the actual width of the cell?
- 0.003 mm
- 3 mm
- 0.3 mm
- 12 000 mm
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Answer: C (0.3 mm) (1)