Stray light hitting the detector will produce erroneous results when the absorba
ID: 1071297 • Letter: S
Question
Stray light hitting the detector will produce erroneous results when the absorbance of a solution is measured. Calculate the apparent absorbance of a solution, if the measured absorbance is 0.750 and 2.00% stray light has entered the system. a) 0.712 b) 0.194 c) 0.178 7 of 15 Which of the following is not an advantage of Fourier transform spectroscopy? a) Fourier transform spectroscopy offers improved signal-to-noise ratio. b) Fourier transform spectroscopy allows for the acquisition of spectra in a very short time. c) Fourier transform spectroscopy is applicable to allimportant regions of the electromagnetic spectrum. 8 of 15 What is an Qptode? a) A device used to increase the number of electrons produced by a photosensitive material. b) A device created by placing a chemically sensitive layer at the end of an optical fiber. c) An optical device used to disperse light into its component wavelengths of 15 9 of 15 Selecting the appropriate wavelength and bandwidth for a spectrophotometric analysis is very important. Which of the following is a correct statement regarding the bandwidth? a) The bandwidth should be as large as possible. b) The bandwidth should be as small as possible. c) The bandwidth should be as large as possible but small compared with the band being measured. 10 of 15 A number of things can happen to light when it strikes a sample. Which of the following best represents what happens to light when it strikes a sample? a) Light striking a sample can be transmitted or absorbed. b) Light striking a sample can be transmitted, absorbed, or reflected. c) Light striking a sample can be transmitted, absorbed, reflected, or scattered.Explanation / Answer
Absorbance, =A(measured)=0.750=Am
Transmittance,T(measured)=Tm
Stray light of wavelength other than selected causes transmittance to be higher .
Am=-log Tm
0.750=-log (Tm
Tm=10^(-0.750)=0.178
Tm=p/po
Tapparant=Tm+r
Also Tapparant=P+Ps/Po+Ps =P+0.02Po/Po+0.02Po=P+0.02Po/1.02Po=0.98 P/Po +0.02=0.98*0.178+0.020=0.194
A(app)=-log Tapp=-log 0.194=0.712