Term
| the photometer puts out a (voltage/current) signal that is (proportional/inverse) to the intensity of the incident (light/electrons) |
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Definition
| voltage, proportional, light |
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Term
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Definition
| Light hits a metal, photons are absorbed by electrons which become excited and produce a current. This is amplified by the photometer and converted to a voltage by the DMM |
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Term
| T/F when taking photometer measurements, you need to hit the photometer with the laser at the same place each time to be accurate |
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Definition
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Term
| why will the DMM still show an output even if the photometer is turned off? |
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Definition
| ambient waves in the air and high input impedance. V=IR. DMM has a high R so a small I is amplified |
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Term
| projection imaging (name two types) and what is done |
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Definition
| radiography, fluoroscopy. beam projects through a patients body casting shadows onto appropriate receptor that converts beam into visible light image |
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Term
| advantages and disadvantages of projection imaging |
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Definition
Advant: large vol can be viewed
disadvant: structures often superimposed so there is interference of image
spatial distortion is not usually a problem |
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Term
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Definition
CT,PET, SPECT, sonography, MRI.
advantage: increased visability
disadvantage: only one slice of a body can be viewed with one image |
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Term
| requirements for suitable body beam |
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Definition
| can penetrate body, produces useful info, harmful interactions are minimal |
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Term
| electromagnetic radiation |
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Definition
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Term
| when particles strike a sample |
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Definition
| 1) reflection 2) transmission 3) absorption |
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Term
| two things that affect minimum resolution of a measurement |
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Definition
| spatial extent and divergence of the source |
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Term
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Definition
| all particles travel in a straight line parallel to each other |
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Term
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Definition
| angualr spread of beam. Parallel beam means zero divergence. It is important to have a collimated source |
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Term
| beneath spatial resolution |
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Definition
| objects much smaller than the distance of the beam |
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Term
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Definition
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Term
| number of photons emitted per second by an isotropic source |
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Definition
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Term
| isotropic source intensity |
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Definition
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Term
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Definition
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Term
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Definition
| L. us this for diergence problems |
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Term
| how does intensity decrease as you move away from a collimated source? |
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Definition
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Term
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Definition
| low powered. absorbed quicly by hemoglobin. stops bleeding |
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Term
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Definition
| high powered. surgical knife. leaves neighboring cells untouched. |
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Term
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Definition
| penetrates deeply. can be used in fluid filled cavities like eyes. cannot be used for precision |
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Term
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Definition
| condensed energy quickly turned into heat. low divergence--> focused on small spot. Produces steam |
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Term
| why is green light of argon preferred over red light of ruby? |
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Definition
| weld made by laser is in pigmented epithelium (furthest layer back in retina). green is more heavily absornedand sharper foci are possible. decreased scar size |
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Term
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Definition
| packed close on retinal surface. 2x rods as cones. |
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Term
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Definition
| only cones. ineffective at low illumination. record info concerning color |
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Term
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Definition
| light must strike foves. best if viewed in a narrow cones. level of illumination |
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Term
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Definition
| distribution of light sensing elements in retina. Equal responses cannot be illicited from adjacent cones. There must be an unexcited cone between two excited cones. View on visual axis |
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Term
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Definition
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Term
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Definition
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Term
| measuring incidence and reflectance in a mirror |
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Definition
| measured from the normal NOT the mirror surface |
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Term
| specular reflection rules |
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Definition
| incidence=reflected. incident ray, normal, and reflected all on the same plane |
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Term
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Definition
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Term
| the more optically dense the medium, the (faster, slower) the light travels and the (higher, lower) the index of refraction |
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Definition
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Term
light traveling from rare to dense
(n rare |
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Definition
| light bends toward normal; and vice versa |
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Term
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Definition
incident and refracted ray and the normal point of incidence all on sam plane.
sin i/sin r= nr/ni or ni*sin i= nr*sinr |
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Term
| light going from rare to dense medium. angle of incidence is zero, ray passes unrefracted |
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Definition
| incidence angle close to 90 will refract less than 90 |
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Term
| a ray from denser to rarer medium does not always... |
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Definition
| progate to rarer medium. Some critical angle less than 90 has an aor of 90 |
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Term
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Definition
| r=90, sin icrit= nr/nisin90=nr/ni |
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Term
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Definition
=nclad/ncore. this will give the angle needed for internal reflection in fiber optics. Alpha is this angle
sinThetacore=cosi |
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Term
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Definition
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Term
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Definition
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Term
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Definition
| T-E/T X100. small dicrepancies indicate general agreement. A large dicrep may indicate bad data reading or that the theory is not applicable. |
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Term
| angle between bench and laser |
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Definition
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Term
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Definition
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Term
| coherent bundle of optical fibers |
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Definition
| fibers must maintain identical relative poisitions of the input amd output faces. Aligned fiber ends needed to transmit image |
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Term
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Definition
| can be used to transfer light, have uneven ends |
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Term
| what limits length of fibrescope? |
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Definition
| spectral capability (what wavlength can be conducted), spectral capacity (how much). limited mostly by this. as length of lightguide increases, transmission decreases. min bending radius becomes larger |
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Term
| index of refraction and velocity formula |
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Definition
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Term
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Definition
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Term
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Definition
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Term
| A student measures theta mirror and theta bench. The problem asks you what the discrepancy is for theta bench. How do you solve? |
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Definition
| calculate what theta bench should be based on the measurement made for theta mirror. Then use eqn: (T-E)/T to solve for discrep. |
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Term
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Definition
| can be used with no direct viewing access. and angiscope is an example. The basic requirement to transfer an image is that the fibers must maintain identical relative positions on the input and output faces of the bundle |
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Term
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Definition
| must have direct viewing capability |
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Term
| describe the characteristics of a bundle of fiber used for illumination |
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Definition
| Incoherent; no specific alignment of the fiber ends is necessary |
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Term
| can ultraviolet rays be transmitted by fiberscopes? |
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Definition
| only with poor efficiency |
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Term
| what makes fiber optics good for laser delivery? |
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Definition
| High transmission, light weight, small size, and flexibility |
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Term
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Definition
| sense changes in specific optical properties of material |
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Term
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Definition
| sense changes in specific optical properties of material |
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Term
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Definition
| use a reagent that changes its optical properties in response to changes in the material of interest. |
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Term
| is a pH sensor direct of indirect? |
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Definition
| indirect; uses pH sensitive agent that changes optical properties in response to pH |
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Term
| is oxygen saturation sensor direct or indirect? |
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Definition
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Term
| how is the amplitude of a sound wave measured? |
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Definition
| by the amount of increase or decrease in pressure above or below the ambient pressure |
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Term
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Definition
SQRT(1/(1+((pi*frequency of wave*sigma)/rho*v)^2))
sigma is mass per unit area and rho*v should be given in mass per unit area per unit time. Frequency given in Hz |
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Term
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Definition
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Term
| the voltage recorded by the DMM is proportional to the (amplitude/frequency) of the sound wave |
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Definition
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Term
| three things can happen to wave energy when it srikes a surface |
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Definition
| absorption, transmission, reflectance |
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Term
| water is a ________ conductor of ultrasound |
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Definition
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Term
| lungs are _______ conductors of ultrasound because _______ |
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Definition
| bad, air filled alveoli scatter it |
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Term
| how must materials differ to form a reflection interference |
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Definition
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Term
| pulses are reflected back to a transducer after reflecting in the body. The reduction and amplitude tells... |
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Definition
| what type of material it was relfected off of |
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Term
| ossicles in ear- what is their purpose? |
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Definition
| transmit pressure wave from ear drum to oval window. convert large amp, low P vibration of eardrum to low amp, high P vibration. Match impedance of air to impedance of fluid in cochlea |
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Term
| a convex lens forms a real or imaginary image? |
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Definition
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Term
| concave lens creates a real or virtual image? |
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Definition
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Term
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Definition
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Term
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Definition
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Term
| image if object is within focal length of convex mirror |
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Definition
| image is upright and virtual |
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Term
| angular magnification eqn |
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Definition
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Term
| diverging lens has a focal length that is always |
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Definition
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Term
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Definition
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Term
| focus is done where the indices of refraction.... |
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Definition
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Term
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Definition
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Term
| The _____ is flatter at its ____ than at its ______, and the ______ is denser in the center and hence refracts more strongly at its core than at its outer layers. |
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Definition
| cornea, margins, center, lens |
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Term
| the length between two wave crests |
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Definition
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Term
| two fundamental properties of travelling waves |
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Definition
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Term
| time interval between wave crests |
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Definition
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Term
| how many crests pass a fixed point per second |
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Definition
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Term
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Definition
|
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Term
|
Definition
| Plancks constant*frequency;;;; 6.63*10^-34 |
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Term
| warmer temp=(longer, shorter) wavelength |
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Definition
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Term
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Definition
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Term
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Definition
| 1 electron volt; 1.6*10-19 |
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Term
| Photons emitted as electrons move down in orbital energy have distinct energies, thus |
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Definition
| these photons have distinct wavelengths or colors |
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Term
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Definition
|
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Term
| what does a collimator do in the prism experiment? |
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Definition
| makes light parallel when hitting prism |
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Term
| in a prism, shorter wavelengths are bent (most or least) |
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Definition
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Term
angle of deviation (D)
Dmin=theta2=30deg |
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Definition
| depends on angle between incident beam and prism |
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Term
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Definition
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Term
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Definition
| blue light focused shorter than red light |
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Term
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Definition
| radiates only a few discrete wavelengths |
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Term
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Definition
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Term
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Definition
| absorbs maximally in violet region |
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Term
| what energy photons are filtered from med equip? |
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Definition
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Term
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Definition
| uses line radiation. radiation associated with nucleus |
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Term
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Definition
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Term
| prism apex should/should not be directly towards the lamp |
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Definition
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Term
|
Definition
| outer ticks are degrees, inner ticks are arc min |
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Term
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Definition
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Term
| minimum resolvable separation |
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Definition
| maximum of the diffraction pattern of one source falls on the first minimum of the diffraction pattern of the other |
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Term
| minimum resolvable separation for circular aperature |
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Definition
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Term
|
Definition
| 1.22*wavelength at speed of light/n*d |
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