Exam 1

Question 1

Robert Hook

Answer 1

used compound microscope in 1665 to observe “cells” from cork

Question 2

Define Cone Cells

Answer 2

the eye receptors of the retina used for sensing color

Question 3

Define Rod Cells

Answer 3

cells distinguishing levels of intensity

Question 4

What is the basic set up of a microscope?

Answer 4

light
lends
source
detector

Question 5

List the forms of electromagnetic radiation in order of increasing wavelength.

Answer 5

Gamma Rays
X-rays
Ultraviolet
Visible - R.O.Y.G.B.I.V.
Infrared
Microwaves
Radio
-AM
-FM

Question 6

Why do biologists primarily use infrared?

Answer 6

use it for biological tissue because of less scattering and deep penetration

Question 7

Define Transparency

Answer 7

allows objects to be seen clearly through it

Question 8

Define Opacity

Answer 8

the condition of lacking transparency

Question 9

What are the properties of light?

Answer 9

wave
-periodic osillation that transmit energy through space
-3 parts; wavelength, amplitude, frequency
particle

Question 10

True or False

All objects emit electromagnetic radiation.

Answer 10

True

Question 11

UV Catastrophe

Answer 11

based on wave theory of light, classical physics predicts that energy increases as wavelength decreases (continuous relationship)

it is not a continuous relationship (bell-curve)

Question 12

What two components are always perpendicular to each other in electromagnetic radiation?

Answer 12

electrical and magnetic

Question 13

Name the three problems to overcome to improve resolution

Answer 13

Chromatic Aberration
Spherical Aberration
Lack of Light

Question 14

Chromatic Aberration

Answer 14

• unequal bending of different wavelengths of light

- creates bluish halo

Question 15

Spherical Aberration

Answer 15

light rays that pass through different parts of lens (center vs periphery) focus to different points

Question 16

Name the types of lens

Answer 16

convex
plano-convex
concave
plano-concave

Question 17

Achromatic Doublet Lens

Answer 17

-look like plano-concave

designed to eliminate chromatic and spherical aberrations inherent in singlet lenses

Question 18

Black-Body Radiation

Answer 18

• an opaque and non-reflective body that is in thermodynamic equilibrium with its surroundings
• an E.M. radiation given off by a this emitter
• at room temperature, the object emits most of its energy as I.R. and absorbs all visible light thus appearing black
  ex) planets and stars

Question 19

Stefan-Boltzmann Law

Answer 19

relates total energy emitted is directly proportional to the 4th power of temperature

Question 20

If two waves with the same frequency and speed are present, the wave with the higher or lower amplitude has greater energy?

Answer 20

higher

Question 21

Abbe’s Theory of Image Formation

Answer 21

Condenser Iris
Condenser Lens
Specimen
Objective Lens
Objective Rear Focal Plane (diffraction on pattern)
-this part determines the specimen using diffraction pattern
(if I don’t get all of the diffraction pattern, I don’t get the entire image)

Question 22

Numerical Aperature

Answer 22

• NA

- measures of light bending by the material

Question 23

True or False

Higher NA = Shorter Working Distance

Answer 23

True

Question 24

What is the difference between Ernest Abbe’s and Sir Raleigh’s limits of resolution equations?

Answer 24

Sir Raleigh’s equations takes into account contributions due to diffraction

Question 25

True or False | Higher NA Objective = Worse Resolution

Answer 25

False

Question 26

Point Spread Function

Answer 26

- P.S.F | - describes the optical systems response to a point source

Question 27

True or False | Resolution depends on the NA and wavelength of light

Answer 27

True

Question 28

True or False | As wavelength gets longer (blue to red) resolution will become better

Answer 28

False

Question 29

Frank - Condon Principle

Answer 29

Electric distribution changes occur more rapidly compared to bond angles and distances

Question 30

Bathochromic Shift

Answer 30

The more conjugation a molecule has, the more it leads to increased shift to longer wavelengths for absorption

Question 31

Why is there a difference of broading peaks between a gas and a solution?

Answer 31

- gases produce sharp absorption and emission bands because of the space between molecules - molecules in solution do not produce sharp absorption/emission bands due to electronic, vibrational and rotational bonds transitions (more molecules to interact with

Question 32

True or False | Most fluorescence molecules are aromatic

Answer 32

True

Question 33

Name 3 Optical Instruments

Answer 33

``` camera binocular telescope spectrophotometer spectrofluorimeter microscope ```

Question 34

Name 3 Critical Components of Optical Instruments

Answer 34

``` light sources optical filters monochrometors polarizers lens detectors ```

Question 35

Name 3 Light Sources

Answer 35

``` sunlight candles gas flame Tungsten-Halogen Lamp Xenon Arc Lamp Lasers LEDs ```

Question 36

Tungsten-Halogen Lamp

Answer 36

- used due to high melting point | - poor emission efficiency (wavelength dependent) (as wavelength increases, molar absorbing decreases)

Question 37

Arc Lamp

Answer 37

- 10 to 100x brighter than Tungsten-Halogen Lamp | - shorter lifespan

Question 38

Name the three types of instability of Arc Lamps

Answer 38

arc wander arc flare arc flutter

Question 39

LASERS

Answer 39

- light amplification by stimulated emission of radiation | - electrons are brought to excited state triggering a chain reaction

Question 40

LEDs

Answer 40

- long operating lifetimes - excellent temporal and spatial stability - lowest operating temperatures due to fully reversible photoelectric effect

Question 41

What does brightness of image depend on?

Answer 41

depends on source of brightness and magnification

Question 42

What are the three types of Optical Filters?

Answer 42

- band pass (allow only a limited number of wavelength of light to pass) - long pass (only allow wavelength of light longer than the specificed cutoff to pass) - neutral density (not specific to wavelength rather used to adjust the intensity or brightness of a light source used for imaging)

Question 43

Monochromator

Answer 43

- diffract light (separate visible wavelengths)

Question 44

Polarized Light

Answer 44

- a light where a component of the E.M. radiation is blocked

Question 45

Birefigent Materials

Answer 45

- materials whose refractive index depends on the polarization and propagation of light - aka a double refraction created from the material

Question 46

Name 3 types of Detectors

Answer 46

- human eye - photomultipler Tube (PMT) - avalanche photodiode (APD) - charged coupled device (CCD)