Microscope Calculations

Find the total magnification: 
Eyepiece = 10X 
Objective lens = 55X  

• 10x

• 55x

• 65x

• 550x

Answer explanation

The total magnification is calculated by multiplying the magnification of the eyepiece (10X) with the magnification of the objective lens (55X). Therefore, the correct answer is 550X.

Field of view is......

• The size of the specimen

• The size of the slide

• The area you can see under the microscope

• The area from which your specimen came

Answer explanation

Field of view refers to the area you can see under the microscope. It determines the extent of the specimen that is visible.

The ________ of the microscope would show you the SMALLEST field of view.

• low power objective

• medium power objective

• high power objective

• ocular

Answer explanation

The high power objective of the microscope provides the smallest field of view.

How many microns (µ) are in a millimeter (mm)?

• 10 µ

• 100 µ

• 1,000 µ

• 0.1 µ

Answer explanation

There are 1,000 microns (µ) in a millimeter (mm).

Here are the settings on a microscope:

Low Power Objective Lens: 4x

Medium Power Objective Lens: 20x

This image shows the field of view under low power (in millimeters) = 4 mm

Calculate the field of view that would appear on medium power.

• 800 µm

• 600 µm

• 900 µm

• 400 µm

Answer explanation

The field of view under medium power is 20x smaller than under low power. Therefore, the field of view on medium power would be 4 mm / 20 = 0.2 mm = 200 µm. The correct choice is 800 µm.

The know field of view is 2.5 mm and an objective of 4x. What is the new field of view if you increase the objective to 40x?

• 0.25 mm

• 25 mm

• 250 mm

• 10 mm

Answer explanation

Increasing the objective from 4x to 40x reduces the field of view. The correct choice is 0.25 mm.

If each division is 100 µm, what is the size of this organism?

• 4 µm

• 400 µm

• 4,000 µm

• 400 mm

Answer explanation

The size of this organism is 400 µm, as each division represents 100 µm and the correct choice is 400 µm.

Doris observed that 8 Smallus Bugus' fit across the field of view, which was calculated to be 1,600 µm.  What is the size of one Smallus Bugus?

• 8 µm

• 1,600 µm

• 200 µm

• 12,800 µm

Answer explanation

The size of one Smallus Bugus is 200 µm because 8 Smallus Bugus' fit across a field of view that is 1,600 µm.

The field of view is 675 μm and a baby starfish ray (leg) takes up 3/4 of you view.  What is the average size of one starfish ray?

• 2,700 μm

• 169 μm

• 900 μm

• 506 μm

Answer explanation

The average size of one starfish ray is 506 μm, as it takes up 3/4 of the field of view (675 μm).