Which of the following statements, A to D, regarding microscopy techniques and principles is correct?
A chloroplast with an actual length of 4.0 μm4.0\ \mu\text{m}4.0 μm is represented in a micrograph with a magnification of ×18,000\times 18,000×18,000. The length of this chloroplast on the micrograph is 72 mm72\text{ mm}72 mm.
Scanning electron microscopes (SEMs) use a beam of electrons passed through a thin specimen to produce extremely high-resolution, two-dimensional images of internal cellular ultrastructure.
Laser scanning confocal microscopes are limited to a maximum resolution of approximately 2 nm2\text{ nm}2 nm because they rely on beams of electrons focused by electromagnetic lenses.
The maximum resolution of a standard light microscope is limited to 0.2 nm0.2\text{ nm}0.2 nm because the wavelength of visible light ranges from 400400400 to 700 nm700\text{ nm}700 nm.
22 exam-style questions on OCR A A Level Biology Cell structure. Each one has a worked solution and a mark scheme showing where the marks go.