1 Which objective lens should you always use when first exam

1. Which objective lens should you always use when first examining a specimen with
a compound microscope?

2. Viruses are much smaller than cells. In fact, the rhinovirus (which causes the
common cold) is about 30 nm, roughly the same size as a ribosome. What kind of
microscope would provide the necessary magnification for viewing this virus?

3. What position should the stage and objective turret be in when you begin to view a sample and when you put your microscope away at the end of class?

Solution

(1)

When you first examine a specimen under the microscope, you should start with lowest magnification objective lenses.

When changing from lower magnification to higher magnification lens from 5X, 10X, 20X, 40X objective lenses the size of the field of view decreases.

(2) Electron microspopy is used to visualize viruses.

Electron microspopy produces an image with resolution as great as 0.1nm, meaning it can help us visualize two particles of size 0.1 nm as two separate particles.

(3) At the end of class, lower the stage and put the microscope back to the low magnification objective lens.