Microscopes

Question 1

What is a microscope?

Answer 1

It is an instrument used to see objects or parts of the object that are too small to be seen by the naked eye

Question 2

What are the concepts of a microscope?

Answer 2

Magnification, Contrast, Resolution, Microscopic field, and Working distance.

Question 3

What is magnification?

Answer 3

It is the ratio of the size of the image to that of the object

Question 4

What is the formula for total magnification?

Answer 4

Total magnification = Magnification of the ocular lens * magnification of the objective lens

Question 5

What is contrast?

Answer 5

The ability to see a particular details against its background. Stain can be used to increase contrast

Question 6

What is Resolution?

Answer 6

The ability of a microscope to show two closely lying points as two different points.

Resolution increases as Magnification increases

Question 7

What is Microscopic field?

Answer 7

The part of the specimen that can be seen under the microscope. It decreases as magnification decreases

Question 8

What is working distance?

Answer 8

It is the distance between the objective lens and the specimen. It decreases as magnification decreases

Question 9

What are the properties of a simple microscope?

Answer 9

Generally considered to be the first microscope.
Combined a convex lens with a holder for specimens
Magnification between 200x and 300x

Question 10

What are the properties of a compound microscope?

Answer 10

Two lenses
Second lens magnifies the image of the first lens
May be binocular or monocular
Magnification up to 1200x
Low resolution

Question 11

What are optical microscopes and their types?

Answer 11

Optical microscopes use visible or invisible light to create image.
The types are: compound, stereo, phase contract, laser scanning confocal, and fluorescence microscope.

Question 12

What are the properties of stereo microscopes?

Answer 12

Specimen is usually lit from above
Used with opaque specimen
Creates 3D images
Low magnification of 10x to 50x
Lower resolution than compound microscopes

Question 13

What are the properties of a phase contrast microscope?

Answer 13

Light object is seen in a dark background
Low magnification which is up to 100x
Used to view everything in a liquid sample
The light is lit from underneath the specimen
A special condenser blocks the light so that only oblique rays hit the object

Question 14

What are the properties of a laser scanning confocal microscope?

Answer 14

Laser beams are emitted from the laser light source
Laser light goes through the objective lens to scan a sample
The fluorescence of the sample reflected from the focal plane, and then visualize the resulting data with a computer
High resolution images
High contrast

Question 15

What are the properties of a fluorescence microscope?

Answer 15

Uses invisible light such as UV light
When UV light hits the specimen it is stained with a fluorescent dye
The fluorescent dye will emit visible light with an increase in the resolution of the object
Allows observation of fluorescence images
It is possible to only observe specific areas by using different fluorescent labels

Question 16

What are the types of electron microscopes?

Answer 16

Scanning and Transmission electron microscopes

Question 17

What are the general properties of electron microscopes?

Answer 17

Uses a beam of electrons to form an image
Uses electromagnetic lenses instead of glass lenses
Very high resolving power

Question 18

What are transmission electron microscope properties?

Answer 18

Gives ultrastructure of the cell
Gives 2D image
Total magnification of over 20,000,000x

Question 19

What are the properties of a scanning electron microscope?

Answer 19

Gives topography image for the surface of the cell
Gives a 3D image
Total magnification of over 20,000x

Question 20

What are other types of microscopes than electron and compound?

Answer 20

X-ray microscope: uses a beam of x-rays to create an image and has higher resolution than optical microscope

Scanning acoustic microscope: employs sound waves to create image

Question 21

How do you carry a microscope?

Answer 21

One hand under the base, and the other holds the arm. The microscope must be upright parallel to your body

Question 22

How do you clean the microscope?

Answer 22

Using lens paper. First all optical parts of the microscope except oil immersion lens starting from the eyepiece, objectives, condenser and then light source. A second lens paper for oil immersion lens only.