An Electron Microscope Must Use Electromagnet "Lenses" Shaped Like Donuts

question 74

Multiple Choice

An electron microscope must use electromagnet "lenses" shaped like donuts to direct the electrons onto the specimen. Why?

• A) Electrons are particles but there are other particles in air as well. Without a vacuum, the electrons would strike and be scattered by the particles within the air.
• B) Electrons are highly radioactive, and the chamber must be completely sealed to prevent them from escaping and contaminating the lab area.
• C) This is the method for fixing the specimen to the slide grid for an electron microscope. Without fixing the specimen by vacuum, it would slide off and we wouldn't be able to visualize it.
• D) All of the answer choices are true.
• E) None of the answer choices is true.

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Definitions:

Service Time Distribution

The statistical distribution of the time taken to serve customers in a queue, affecting waiting times and service efficiency.

Number of Channels

Refers to the distinct paths or routes through which a company distributes its products or services to customers.

Number of Phases

refers to the distinct stages in a project, process, or lifecycle, often marked by key milestones or transitions.

Population Size

The total number of members in a group that is being studied or for which data is being collected.