B1.1 Measuring Cells

Question 1

What is the formula of Magnification?

Answer 1

Size of Image / Size of Real Object

Question 2

What is the triangle of Image, Actual Size and Magnification?

Answer 2

Image Size / Actual Size x Magnification
For example if you know the actual size and magnification then you can multiply them together to get the Image Size.

Question 3

You are looking at onion cells under a microscope. The cells on the slide appear to measure 5 mm with a magnification of x200. What is the actual size of the cell in micrometres (µm)?

Answer 3

Step 1: list out what you know from the information given
Step 2: convert the units

Image = 5mm = 5000µm

Step 3: write out the formula (and rearrange if necessary)

A=I/M

Step 4: plug the numbers into the formula

A=5000/200

Step 5: do the calculation

5000/200=25µm

Question 4

A red blood cell is 7.5 µm in diameter. It is magnified 2000 times. Calculate the diameter of the image
seen through the microscope in millimetres.

Answer 4

7.5µm x 2000 = 15000µm = 15mm