Microscopy

Question 1

how do you calculate the total magnification of a microscope?

Answer 1

magnification of eyepiece lens x magnification of objective lens.

Question 2

Define magnification.

Answer 2

The number of times bigger an image appears compared to the size of the real object.

Question 3

Define resolution.

Answer 3

The smallest distance between two objects that can be distinguished.

Question 4

How does a light microscope work?

Answer 4

Passes a beam of light through a specimen which travels through the eyepiece lens, allowing the specimen to be observed.

Question 5

What are the advantages of light microscopes? (4)

Answer 5

● Inexpensive
● Easy to use
● Portable
● Observe both dead and living specimens

Question 6

What is the disadvantage of light microscopes?

Answer 6

Limited resolution and magnification

Question 7

What is the advantage of electron microscopes?

Answer 7

Greater magnification and higher resolution.

Question 8

How have electron microscopes enabled scientists to develop their understanding of cells?

Answer 8

● Allow small sub-cellular structures (e.g. mitochondria, ribosomes) to be observed in detail.
● Enable scientists to develop more accurate explanations about how cell structure relates to function.

Question 9

What are the disadvantages of electron microscopes? (4)

Answer 9

● Expensive
● Large so less portable
● Require training to use
● Only dead specimens can be observed

Question 10

How can the magnification of an image be calculated?

Answer 10

magnification = size of image / size of real object