THE MICROSCOPE

Question 1

The ratio of the apparent size of an object as seen through the microscope & the
actual size of the object

Answer 1

Magnification

Question 2

• The ability of the lens to clearly separate or distinguish two points of two lines
  individually in the image.
• It is determined by the shortest wavelength of visible light & maximum numerical
  aperture

Answer 2

Resolution/Resolving Power

Question 3

• A measurement of the ability of the condenser and the objective lens to gather light.
• Scanner : 4x : 0.10
• LPO : 10X : 0.25
• HPO : 40X : 0.65
• OIO : 100X : 1.25

Answer 3

. Numerical Aperture

Question 4

• Thickness of the object that maybe seen at one time under focus.
• Distance between the center of a lens or curved mirror and its focus

Answer 4

Focal length

Question 5

• Distance between the front lens of the objective lens & the top of the cover glass when the
  specimen is in focus.

Answer 5

Working distance

Question 6

• Refers to quality of the objectives & eyepiece where practically no change in focus has to be
  made when objective is substituted for another

Answer 6

Parfocal

Question 7

• Bending of light rays away from the objective lens when light passes from the glass of the microscope slide to the air.

Answer 7

Refractive Index

Question 8

• First microscope.
• Created in the 17th century by Antony van Leeuwenhoek, who combined a convex lens with a holder for specimens.
• 200 – 300x Magnification
• Not used often today because the introduction of a second lens led to the more powerful compound microscope

Answer 8

Simple Microscope

Question 9

• Two lenses
• Better magnification than a simple microscope
• Bright field microscopes (the specimen is lit from underneath, and they can be binocular or monocular) provide a magnification of 1,000 times, which is considered to be high, although the resolution is low.
• Allows users to take a close look at objects too small to be seen with the naked eye, including individual cells.

Answer 9

Compound Microscope

Question 10

• Stained tissue is examined with ordinary light passing through the preparation.
• The microscope includes an optical system and mechanisms to move and focus the specimen

Answer 10

Bright field microscopes

Question 11

• Tissue sections are usually irradiated with ultraviolet (UV) light and the emission is in the visible portion of the spectrum.
• Fluorescent substances appear bright on a dark background

Answer 11

Fluorescence Microscopy

Question 12

• uses a lens system that produces visible images from transparent objects and, importantly, can be used with living, cultured cells

Answer 12

Phase-Contrast Microscopy

Question 13

-Allows the recognition of stained or unstained structures made of highly organized subunits.
-Tissue structures containing oriented macromolecules are located between the two filters, they appear as bright structures against a dark background.

Answer 13

Polarizing Microscopy

Question 14

• Uses electrons rather than light for image formation.
• Samples are scanned in vacuum or near vacuum conditions, so they must be specially prepared by first undergoing dehydration and then being coated with a thin layer of a conducive material, such as gold.

Answer 14

Scanning Electron Microscope (SEM)

Question 15

• Uses electrons rather than light for image formation.
• Samples are scanned in vacuum or near vacuum conditions, so they must be specially prepared by first undergoing dehydration and then being coated with a thin layer of a conducive material, such as gold.
• After the item is prepared and placed in the chamber, the SEM produces a 3-D, black-and white image on a computer screen.

Answer 15

Scanning Electron Microscope (SEM)

Question 16

-uses electrons in creating a magnified image
- Uses a slide preparation to obtain a 2-D view of specimens, so it’s more suited for viewing objects with some degree of transparency.
- Offers a high degree of both magnification and resolution

Answer 16

Transmission Electron Microscope (TEM)

Question 17

used to support and adjust the parts

Answer 17

Mechanical Parts

Question 18

used to enlarge the specimen

Answer 18

Magnifying Parts

Question 19

used to provide light

Answer 19

Illuminating Parts

Question 20

bottom post portion that supports the entire
microscope, provides stability and support for the
microscope when it is upright. The base also typically
holds the illuminator, or light source

Answer 20

• Base

Question 21

part above the base that supports the other parts

Answer 21

Pillar

Question 22

allows for tilting for the convenience of the user

Answer 22

Inclination joint

Question 23

connects the eyepiece tube to the base ,curve or slanted part which is held while carrying the microscope

Answer 23

Arm

Question 24

is a platform for the slides, which hold the specimen.

Answer 24

Stage and stage clip

Question 25

attached to the arm and bears the lenses

Answer 25

Body tube

Question 26

cylindrical structure on the top of the body tube that holds the ocular lenses

Answer 26

Draw tube

Question 27

contains the objective lenses. Microscope users can rotate this part to switch between the objective lenses and adjust the magnification power

Answer 27

Revolving nosepiece

Question 28

lies atop the nose piece and keeps dust from settling on the objectives

Answer 28

Dust shield

Question 29

moves stage (or body tube) up and down, used to focus the image on the microscope under low or medium power

Answer 29

Coarse Adjustment Knob

Question 30

small knob, used to focus of your specimen after using the coarse adjustment knob

Answer 30

Fine Adjustment Knob

Question 31

contains the ocular lens, which the user looks through to see the magnified specimen, further magnify the image produced by the objective lenses by 5x to 15x

Answer 31

Ocular/ Eyepiece

Question 32

combine with the eyepiece lens to increase magnification levels. Microscopes generally feature three or four objective lenses, with magnification levels ranging 4x to 100x.

Answer 32

Objective lenses

Question 33

microscopes require a light source for viewing. This can come in the form of a built in, low-voltage illuminator light, or a mirror that reflects an external light source like sunlight

Answer 33

Illuminator or Electric Lamp

Question 34

has a concave and plane surface to gather and direct light in order to illuminate the object

Answer 34

Mirror

Question 35

focus the light onto the specimen, concentrating light rays on the specimen

Answer 35

Condenser

Question 36

controls the amount of light reaching the specimen and regulates the light necessary to obtain a clear view of the object

Answer 36

Iris Diaphragm