A-LevelBiologyCell structureFeb/Mar 2023Paper 1 Q21 Mark
A student calibrated an eyepiece graticule using a stage micrometer. • Each division of the stage micrometer was 0.01 mm. • With a ×10 magnification objective lens, 10 eyepiece graticule units matched 10 divisions on the stage micrometer. The same microscope was used with a ×40, instead of a ×10, magnification objective lens to measure the diameter of an alveolus. The diameter of the alveolus was found to be 96 eyepiece graticule units. The eyepiece lens was not changed. What is the best estimate for the diameter of the alveolus?
A0.960 mm
B3.84 mm
C240 μm
D384 µm
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The correct answer is C. This question tests the candidate's understanding of cell structure within the Biologysyllabus. The examiner's mark scheme requires...
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