# Shared Flashcard Set

## Details

3LC Final (UC Irvine)
Web works and manual material for final
113
Physics
12/02/2012

Term
 the photometer puts out a (voltage/current) signal that is (proportional/inverse) to the intensity of the incident (light/electrons)
Definition
 voltage, proportional, light
Term
 photoelectric effect
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
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
Definition
 true
Term
 why will the DMM still show an output even if the photometer is turned off?
Definition
 ambient waves in the air and high input impedance. V=IR. DMM has a high R so a small I is amplified
Term
 projection imaging (name two types) and what is done
Definition
 radiography, fluoroscopy. beam projects through a patients body casting shadows onto appropriate receptor that converts beam into visible light image
Term
Definition
 Advant: large vol can be vieweddisadvant: structures often superimposed so there is interference of imagespatial distortion is not usually a problem
Term
 tomographic imaging
Definition
 CT,PET, SPECT, sonography, MRI.advantage: increased visabilitydisadvantage: only one slice of a body can be viewed with one image
Term
 requirements for suitable body beam
Definition
 can penetrate body, produces useful info, harmful interactions are minimal
Term
Definition
 light waves and paricles
Term
 when particles strike a sample
Definition
 1) reflection 2) transmission 3) absorption
Term
 two things that affect minimum resolution of a measurement
Definition
 spatial extent and divergence of the source
Term
 collimated
Definition
 all particles travel in a straight line parallel to each other
Term
 beam dvergence
Definition
 angualr spread of beam. Parallel beam means zero divergence. It is important to have a collimated source
Term
 beneath spatial resolution
Definition
 objects much smaller than the distance of the beam
Term
 spatial resolution
Definition
 improved by collimation
Term
 number of photons emitted per second by an isotropic source
Definition
 Phi*4*pi*r^2
Term
 isotropic source intensity
Definition
 X*1/r^2
Term
 tan (theta/2)=
Definition
 D/2/d
Term
 r*theta=
Definition
 L. us this for diergence problems
Term
 how does intensity decrease as you move away from a collimated source?
Definition
 it doesnt
Term
 Argon Laser
Definition
 low powered. absorbed quicly by hemoglobin. stops bleeding
Term
 Co2 laser
Definition
 high powered. surgical knife. leaves neighboring cells untouched.
Term
 YAG laser
Definition
 penetrates deeply. can be used in fluid filled cavities like eyes. cannot be used for precision
Term
 medical lasers
Definition
 condensed energy quickly turned into heat. low divergence--> focused on small spot. Produces steam
Term
 why is green light of argon preferred over red light of ruby?
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
Term
 rods and cones
Definition
 packed close on retinal surface. 2x rods as cones.
Term
 fovea
Definition
 only cones. ineffective at low illumination. record info concerning color
Term
 acuity
Definition
 light must strike foves. best if viewed in a narrow cones. level of illumination
Term
 resolving power of eye
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
Term
 specular reflection
Definition
 smooth like a mirror
Term
 diffuse reflector
Definition
 bumpy
Term
 measuring incidence and reflectance in a mirror
Definition
 measured from the normal NOT the mirror surface
Term
 specular reflection rules
Definition
 incidence=reflected. incident ray, normal, and reflected all on the same plane
Term
 index of refraction, n
Definition
 n=c/v
Term
 the more optically dense the medium, the (faster, slower) the light travels and the (higher, lower) the index of refraction
Definition
 slower, higher
Term
 light traveling from rare to dense(n rare
Definition
 light bends toward normal; and vice versa
Term
 Refraction
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
Term
 light going from rare to dense medium. angle of incidence is zero, ray passes unrefracted
Definition
 incidence angle close to 90 will refract less than 90
Term
 a ray from denser to rarer medium does not always...
Definition
 progate to rarer medium. Some critical angle less than 90 has an aor of 90
Term
 critical angle
Definition
 r=90, sin icrit= nr/nisin90=nr/ni
Term
 sin icrit
Definition
 =nclad/ncore. this will give the angle needed for internal reflection in fiber optics. Alpha is this anglesinThetacore=cosi
Term
 cos i=
Definition
 sqrt(1-sin^2 i)
Term
 sin alpha crit=
Definition
Term
 discrepancy
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.
Term
 angle between bench and laser
Definition
 theta bench.
Term
 theta mirror=
Definition
 1/2 theta bench
Term
 coherent bundle of optical fibers
Definition
 fibers must maintain identical relative poisitions of the input amd output faces. Aligned fiber ends needed to transmit image
Term
 incoherent bundles
Definition
 can be used to transfer light, have uneven ends
Term
 what limits length of fibrescope?
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
Term
 index of refraction and velocity formula
Definition
 n=c/v
Term
 theta bench
Definition
 i+r angles
Term
 theta mirror
Definition
 =i
Term
 A student measures theta mirror and theta bench. The problem asks you what the discrepancy is for theta bench. How do you solve?
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.
Term
 fibrescope
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
Term
 endoscope
Definition
 must have direct viewing capability
Term
 describe the characteristics of a bundle of fiber used for illumination
Definition
 Incoherent; no specific alignment of the fiber ends is necessary
Term
 can ultraviolet rays be transmitted by fiberscopes?
Definition
 only with poor efficiency
Term
 what makes fiber optics good for laser delivery?
Definition
 High transmission, light weight, small size, and flexibility
Term
 direct sensor
Definition
 sense changes in specific optical properties of material
Term
 direct sensor
Definition
 sense changes in specific optical properties of material
Term
 indirect sensor
Definition
 use a reagent that changes its optical properties in response to changes in the material of interest.
Term
 is a pH sensor direct of indirect?
Definition
 indirect; uses pH sensitive agent that changes optical properties in response to pH
Term
 is oxygen saturation sensor direct or indirect?
Definition
 direct
Term
 how is the amplitude of a sound wave measured?
Definition
 by the amount of increase or decrease in pressure above or below the ambient pressure
Term
 transmission coefficient
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
Term
 v=
Definition
 freq*wavelength
Term
 the voltage recorded by the DMM is proportional to the (amplitude/frequency) of the sound wave
Definition
 amplitude
Term
 three things can happen to wave energy when it srikes a surface
Definition
 absorption, transmission, reflectance
Term
 water is a ________ conductor of ultrasound
Definition
 good
Term
 lungs are _______ conductors of ultrasound because _______
Definition
 bad, air filled alveoli scatter it
Term
 how must materials differ to form a reflection interference
Definition
 acoustic impedance
Term
 pulses are reflected back to a transducer after reflecting in the body. The reduction and amplitude tells...
Definition
 what type of material it was relfected off of
Term
 ossicles in ear- what is their purpose?
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
Term
 a convex lens forms a real or imaginary image?
Definition
 real
Term
 concave lens creates a real or virtual image?
Definition
 virtual
Term
 Mgnification eqn
Definition
 -1/o
Term
Definition
 the image is upside down
Term
 image if object is within focal length of convex mirror
Definition
 image is upright and virtual
Term
 angular magnification eqn
Definition
 m=theat len/theta object
Term
 diverging lens has a focal length that is always
Definition
 negative
Term
 microscope eqn
Definition
 m=I(1)L/O(1)f(2)
Term
 focus is done where the indices of refraction....
Definition
 differ most
Term
 fish do focusing at the
Definition
 len
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.
Definition
 cornea, margins, center, lens
Term
 the length between two wave crests
Definition
 wavelength
Term
 two fundamental properties of travelling waves
Definition
 wavelength and frequency
Term
 time interval between wave crests
Definition
 period
Term
 how many crests pass a fixed point per second
Definition
 frequency
Term
 v=Freq*wavelength==
Definition
 wavelength/period
Term
 E=hc/wavelength
Definition
 Plancks constant*frequency;;;; 6.63*10^-34
Term
 warmer temp=(longer, shorter) wavelength
Definition
 shorter
Term
 En=
Definition
 13.6eV/n^2
Term
 eV
Definition
 1 electron volt; 1.6*10-19
Term
 Photons emitted as electrons move down in orbital energy have distinct energies, thus
Definition
 these photons have distinct wavelengths or colors
Term
Definition
Term
 what does a collimator do in the prism experiment?
Definition
 makes light parallel when hitting prism
Term
 in a prism, shorter wavelengths are bent (most or least)
Definition
 most
Term
 angle of deviation (D)Dmin=theta2=30deg
Definition
 depends on angle between incident beam and prism
Term
 prism equation
Definition
 n2=2sin(30+Dmin/2)
Term
 chromatic abberration
Definition
 blue light focused shorter than red light
Term
 gas tube
Definition
 radiates only a few discrete wavelengths
Term
 filament
Definition
 continuous spectrum
Term
 xanthophyll
Definition
 absorbs maximally in violet region
Term
 what energy photons are filtered from med equip?
Definition
 low energy
Term
 MRI
Definition
Term
 gas lamp
Definition
Term
 prism apex should/should not be directly towards the lamp
Definition
 should not
Term
 vernier scale
Definition
 outer ticks are degrees, inner ticks are arc min
Term
 diffraction equation
Definition
 dsin(theta)=n*wavelength
Term
 minimum resolvable separation
Definition
 maximum of the diffraction pattern of one source falls on the first minimum of the diffraction pattern of the other
Term
 minimum resolvable separation for circular aperature
Definition
 alpha=(1.22*waelength)/d
Term
 alpha=
Definition
 1.22*wavelength at speed of light/n*d
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