BIO 245 LATEST 2026 TEST PAPER QUESTIONS AND
SOLUTIONS RATED A+
✔✔Who invented the first compound microscope - ✔✔Zecharias Janssen
✔✔When did Zecharias Janssen invent the first compound microscope - ✔✔Around the
beginning of the 17th century
✔✔What was the magnification of Zecharias Janssen's compound microscope? - ✔✔3X
to 9X
✔✔Van Leeuwenhoek - ✔✔First to observe bacteria
✔✔T or F
Leeuwenhoek's microscope used to see bacteria was a compound microscope -
✔✔False
✔✔Magnifications of Leeuwenhook's simple microscope - ✔✔Magnifications to 200x
✔✔More important then greater magnification for its time, Leeuwenhoek's microscope
also had greater _______________________ - ✔✔resolution
✔✔In a simple lense, ________________ causes the bending of light rays, resulting in
a _____________ image than that of the original - ✔✔refraction; larger
✔✔How does a simple lens work? - ✔✔Refraction
Results in image larger than size of original
✔✔Refraction - ✔✔The bending of a wave as it passes at an angle from one medium to
another, due to the change in speed causing a change in direction, with the degree of
change dependent on the angle of the incoming light
✔✔compound lens system - ✔✔Contains at least two lenses- the real image produced
by the first lens becomes the object for the second lens that magnifies it as a larger
virtual image
✔✔Compound scopes usually use the combo of what two lenses? - ✔✔Ocular and
objective lenses
✔✔What is the total magnification of a compound lens? - ✔✔The product of the
magnification of each lens
✔✔Why cant we see smaller objects by adding more (or stronger) lenses? -
✔✔Magnification can increase, but beyond a point the image is no longer clear
, ✔✔_________________ puts practical limits on magnification - ✔✔Resolution
✔✔Resolution - ✔✔the ability of the lenses to distinguish small objects close together
✔✔What is the human eye's resolution limit? - ✔✔0.1 mm
✔✔Resolving power variable - ✔✔d - the resolution distance
✔✔We want the resolving power variable to be - ✔✔small
✔✔What is the equation for resolving power "d"? - ✔✔D = wavelength/numerical
aperture of the condensor + numerical aperture o the objective
✔✔Numerical aperture - ✔✔A measure of the light passing from the object and into the
objective to maximize optical clarity ad resolution
✔✔What is the wavelength of light? - ✔✔520 nm
✔✔What is the numerical aperture of the average lense? - ✔✔Approx. 0.94
✔✔Regarding resolving power (d) for a typical microscope, we can't distinguish things
closer (or thinner) than about _______ micrometers - ✔✔0.28
✔✔How to decrease resolving power (d) numerator - ✔✔Use illumination source with
shorter wavelength or greater Numerical aperture
✔✔Electron microscope - ✔✔microscope that forms an image by focusing beams of
electrons onto a specimen
✔✔Three wave characteristics - ✔✔Amplitude, Wavelength, and frequency
✔✔What is the effect of wavelength on resolution? - ✔✔Resolution can be improved
with shorter wavelength
✔✔How to make the resolving power equation denominator larger - ✔✔With a better
lens
This increases numerical aperture
✔✔What are the six types of light microscopy? - ✔✔Brightfield
Darkfield
Phase Contrast
Differential Interference Contrast (DIC) microscopes
SOLUTIONS RATED A+
✔✔Who invented the first compound microscope - ✔✔Zecharias Janssen
✔✔When did Zecharias Janssen invent the first compound microscope - ✔✔Around the
beginning of the 17th century
✔✔What was the magnification of Zecharias Janssen's compound microscope? - ✔✔3X
to 9X
✔✔Van Leeuwenhoek - ✔✔First to observe bacteria
✔✔T or F
Leeuwenhoek's microscope used to see bacteria was a compound microscope -
✔✔False
✔✔Magnifications of Leeuwenhook's simple microscope - ✔✔Magnifications to 200x
✔✔More important then greater magnification for its time, Leeuwenhoek's microscope
also had greater _______________________ - ✔✔resolution
✔✔In a simple lense, ________________ causes the bending of light rays, resulting in
a _____________ image than that of the original - ✔✔refraction; larger
✔✔How does a simple lens work? - ✔✔Refraction
Results in image larger than size of original
✔✔Refraction - ✔✔The bending of a wave as it passes at an angle from one medium to
another, due to the change in speed causing a change in direction, with the degree of
change dependent on the angle of the incoming light
✔✔compound lens system - ✔✔Contains at least two lenses- the real image produced
by the first lens becomes the object for the second lens that magnifies it as a larger
virtual image
✔✔Compound scopes usually use the combo of what two lenses? - ✔✔Ocular and
objective lenses
✔✔What is the total magnification of a compound lens? - ✔✔The product of the
magnification of each lens
✔✔Why cant we see smaller objects by adding more (or stronger) lenses? -
✔✔Magnification can increase, but beyond a point the image is no longer clear
, ✔✔_________________ puts practical limits on magnification - ✔✔Resolution
✔✔Resolution - ✔✔the ability of the lenses to distinguish small objects close together
✔✔What is the human eye's resolution limit? - ✔✔0.1 mm
✔✔Resolving power variable - ✔✔d - the resolution distance
✔✔We want the resolving power variable to be - ✔✔small
✔✔What is the equation for resolving power "d"? - ✔✔D = wavelength/numerical
aperture of the condensor + numerical aperture o the objective
✔✔Numerical aperture - ✔✔A measure of the light passing from the object and into the
objective to maximize optical clarity ad resolution
✔✔What is the wavelength of light? - ✔✔520 nm
✔✔What is the numerical aperture of the average lense? - ✔✔Approx. 0.94
✔✔Regarding resolving power (d) for a typical microscope, we can't distinguish things
closer (or thinner) than about _______ micrometers - ✔✔0.28
✔✔How to decrease resolving power (d) numerator - ✔✔Use illumination source with
shorter wavelength or greater Numerical aperture
✔✔Electron microscope - ✔✔microscope that forms an image by focusing beams of
electrons onto a specimen
✔✔Three wave characteristics - ✔✔Amplitude, Wavelength, and frequency
✔✔What is the effect of wavelength on resolution? - ✔✔Resolution can be improved
with shorter wavelength
✔✔How to make the resolving power equation denominator larger - ✔✔With a better
lens
This increases numerical aperture
✔✔What are the six types of light microscopy? - ✔✔Brightfield
Darkfield
Phase Contrast
Differential Interference Contrast (DIC) microscopes
