SEMMELWEIS UNIVERSITY Medical
Biophysics I. Semifinal - Practice topics
Questions With Complete Solutions
What kind of image is formed by a compound light microscope? Virtual, magnified and
inverted
What is the total magnification of a light microscope if the objective magnification is 100x and
the ocular magnification is 20x? 100*20= 2000
Describe the steps of the eyepiece scale calibration process. 1.eyepiece scale is placed in
the intermediate image plane (unknown units)2.place a stage micrometer (with known units) as a
''specimen'' 3.focus the eyepiece scale and the micrometer on one another 4.calculate the
calibration factor by dividing the known length of the stage micrometer by the number of rules of
the eyepiece scale.
What prisms are present in the Abbe-refractometer? Illuminating prism (rough surface),
measuring prism (flint glass with high index of refraction) and Amici prisms (restores dispersed
light to white light or vise versa)
, SEMMELWEIS UNIVERSITY Medical
Biophysics I. Semifinal - Practice topics
Questions With Complete Solutions
What sample can be measured with the Abbe-refractometer? Solutions with an index of
refraction lower than that of the
measuring prism (because we want snell's window)
What is the role of Amici prism? To restore dispersed light into white light (or vice versa)
What is optical dispersion? Phenomenon in which white light is decomposed into
component
colors due to the dependence of refractive index on frequency
Factors influencing the value of index of refraction. Solvent concentration in dilute
solution, the frequency, temperature
(makes fluids less viscous so light travels faster)
Formation of Snell circle. Grazing rays from lower index of refraction medium, refract at
the boundary and make critical angles at the medium with the higher index of refraction, the
critical angles form the borders of a cone of bright light.
, SEMMELWEIS UNIVERSITY Medical
Biophysics I. Semifinal - Practice topics
Questions With Complete Solutions
How do you determine concentration by refractometry? In case of dilute solutions
n1=n0+k*c
What is the refractive index of distilled water? 1.33
Definition of absorption spectrum. Absorbance as a function of wavelength. Unique to
every element.
What information can you obtain from an absorption spectrum? Concentration of
solutions (based on intensity change) and the
electronic structure of the atom.
How do you determine concentration by absorption photometry? Beer lamberts law: valid
for dilute solutions log(Jo/J)=ext.coeff*c*xExt.coeff. depends on the type of material and the
wavelength.
Define optical density (absorbance). =log(Jo/J)
Biophysics I. Semifinal - Practice topics
Questions With Complete Solutions
What kind of image is formed by a compound light microscope? Virtual, magnified and
inverted
What is the total magnification of a light microscope if the objective magnification is 100x and
the ocular magnification is 20x? 100*20= 2000
Describe the steps of the eyepiece scale calibration process. 1.eyepiece scale is placed in
the intermediate image plane (unknown units)2.place a stage micrometer (with known units) as a
''specimen'' 3.focus the eyepiece scale and the micrometer on one another 4.calculate the
calibration factor by dividing the known length of the stage micrometer by the number of rules of
the eyepiece scale.
What prisms are present in the Abbe-refractometer? Illuminating prism (rough surface),
measuring prism (flint glass with high index of refraction) and Amici prisms (restores dispersed
light to white light or vise versa)
, SEMMELWEIS UNIVERSITY Medical
Biophysics I. Semifinal - Practice topics
Questions With Complete Solutions
What sample can be measured with the Abbe-refractometer? Solutions with an index of
refraction lower than that of the
measuring prism (because we want snell's window)
What is the role of Amici prism? To restore dispersed light into white light (or vice versa)
What is optical dispersion? Phenomenon in which white light is decomposed into
component
colors due to the dependence of refractive index on frequency
Factors influencing the value of index of refraction. Solvent concentration in dilute
solution, the frequency, temperature
(makes fluids less viscous so light travels faster)
Formation of Snell circle. Grazing rays from lower index of refraction medium, refract at
the boundary and make critical angles at the medium with the higher index of refraction, the
critical angles form the borders of a cone of bright light.
, SEMMELWEIS UNIVERSITY Medical
Biophysics I. Semifinal - Practice topics
Questions With Complete Solutions
How do you determine concentration by refractometry? In case of dilute solutions
n1=n0+k*c
What is the refractive index of distilled water? 1.33
Definition of absorption spectrum. Absorbance as a function of wavelength. Unique to
every element.
What information can you obtain from an absorption spectrum? Concentration of
solutions (based on intensity change) and the
electronic structure of the atom.
How do you determine concentration by absorption photometry? Beer lamberts law: valid
for dilute solutions log(Jo/J)=ext.coeff*c*xExt.coeff. depends on the type of material and the
wavelength.
Define optical density (absorbance). =log(Jo/J)
