Microscopes +magnification calculations

Question 1

What er the parts that microscope consists of?

Answer 1

Eyepiece lens, slide, fine focusing wheel, coarse focusing wheel, objective lens, stage, mirror, light, base, arm, diaphragm.

Question 2

State the definition for magnification?

Answer 2

The ratio of image size to object size- the number of times bigger the image is compared to the opbject.

Question 3

State the definition for resolution?

Answer 3

A measure of the microscope ability to distinguish between two points. It allows more details to be seen.

Question 4

Compare the pros and cons of using light and electron microscopy.

Answer 4

Light:
1. Can see images in natural colours.
2. Limited field of view.
3. Can view living and moving objects.
4. Cheap and easy preparation.
5. Lower resolution and magnification.

Electron:
1. Difficult and expesive preparation.
2. Images are seen in black and white.
3. Can only view dead or inert objects.
4. Higher magnification and resolution

Question 5

Explain how Transmission electron microscope works?

Answer 5

Ypu have to prepare a thin slice of the specimen quite carefully and sit it in a vacuum cahmber in the middle of the machine. After this, ypu fire an electron beam down through the specimen from a giant electron gun at the top.The gun uses electromagnetic coils and high voltages. The faster they travel the smaller the waves they form and the more detailed images they show up.When they reach their top speed it zooms thrpough the specimen and outer the other side where more coils focus them to form an image on a screen. The most powerful electron microspcope.

Question 6

Explain how Scanning electron microscope works?

Answer 6

It uses powerful gun of electrons that shoots an electron beam down at the specimen. A series of electromagnetic coils pulls the beam back and forth, scanning it slowly and systematically across the specimen surface. Instead of travelling through the specimen the electron beam bounces off it. Less powerful than TEMs, but specimen need less preparation and they produce sharp, 3D images.

Question 7

Why staining is needed in microscopy?

Answer 7

To increase the contrast because many biological tissues don’t have much colour of their own. Also, many cellular components are made up of the same materials so there is not much contrast between them.

Question 8

Convert centimeters to milimeters

Answer 8

x10

Question 9

Convert millimeters to micrometers

Answer 9

x1000

Question 10

Convert micrometers to nanometers

Answer 10

x1000

Question 11

Magnification equation?

Answer 11

Magnification=image size/actual size.