INTRODUCTION
MICROSCOPE PARTS MAGNIFICATION RESOLUTION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Low magnification
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Cannot observe living specimens
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High resolution
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None of the above
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Detailed explanation-1: -SEMs usually use acceleration voltages up to 30 kV, while TEM users can set it in the range of 60–300 kV. The magnifications that TEMs offer are also much higher compared to SEMs. TEM users can magnify their samples by more than 50 million times, while for the SEM, this is limited to 1–2 million times.
Detailed explanation-2: -Electron microscopes are the most powerful type of microscope, capable of distinguishing even individual atoms. However, these microscopes cannot be used to image living cells because the electrons destroy the samples.
Detailed explanation-3: -However, TEMs also present some disadvantages: i) The instruments are very large and expensive. ii) TEMs require special housing and maintenance because they are sensitive to mechanical vibration, fluctuation of electromagnetic fields, and variation of cooling water.
Detailed explanation-4: -Limited sampling: a typical field of view for a HR-TEM image is no more than 100 nm2. Complex image interpretation: all TEM images (and diffraction patterns) are 2D projections of 3D structures. Possibility of electron beam damage, especially for light elements, biological samples, and soft materials. More items