A student calibrated an eyepiece graticule using a stage micrometer. - Each division of the stage micrometer was $$$0.01 \mathrm{~mm}$$$. - With a $$$\times 10$$$ magnification objective lens, 10 eyepiece graticule units matched 10 divisions on the stage micrometer. The same microscope was used with $$$a \times 40$$$, instead of a $$$\times 10$$$, 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?

$0.960 \mathrm{~mm}$

$ 3.84 \mathrm{~mm}$

$240 \mu \mathrm{m}$

$384 \mu \mathrm{m}$

Biology

IGCSE&ALevel

CAIE

Exam No：9700_m23_qp_12 Year：2023 Question No：2

Answer:

Knowledge points:

1.1.1 Candidates should be able to:make temporary preparations of cellular material suitable for viewing with a light microscope

1.1.2 Candidates should be able to:draw cells from microscope slides and photomicrographs

1.1.3 Candidates should be able to:calculate magnifications of images and actual sizes of specimens from drawings, photomicrographs and electron micrographs (scanning and transmission)

1.1.4 Candidates should be able to: use an eyepiece graticule and stage micrometer scale to make measurements and use the appropriate units, millimetre (mm), micrometre (µm) and nanometre (nm)

1.1.5 Candidates should be able to: define resolution and magnification and explain the differences between these terms, with reference to light microscopy and electron microscopy

Answer:

Knowledge points:

Solution:

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