Laboratory Equipment: Spectrophotometer Quiz

1. A spectrophotometer measures
light given off by a substance
light changed (change in wavelength) by a substance
light that passes through a substance
light that is fluoresced by a substance

2. Ultraviolet light
has a short wavelength
is measured at 185 to 300 nm
is harmful to human eyes
all of the above

3. Beer's law states that the absorbance equals
(extinction coefficient)*(light path)*(concentration)
2 - log % Transmission
natural log of the concentration times the light path length
(extinction coefficient)*(light path)*(concentration) and 2 - log % Transmission 
(extinction coefficient)*(light path)*(concentration) and natural log of the concentration times the light path length 

4. % Transmission = %T = 100*(I/Io), where Io equals
light reaching the photocell
light striking the cuvette
1% of the incidence light

5. Select the single best answer.  The blank for a spectrophotometer should be composed of
water
uninoculated medium
empty cuvette
liquid as defined in the experiment protocol

6. The purpose of a blank is
to cancel readings due to the color of the reagents
to account for imperfections in the cuvette
to account for imperfections in the cuvette and to cancel readings due to the absorbance of the reagents

   

On to Water Bath