UV Luminance Spectroscopy Why must the radiation source for fluorescence spectrometry be more powerful than for absorption spectroscopy? None of these To allow for scattering by the sample Because the magnitude of the output signal is proportional to the power of the incident radiation Because the sample won't fluoresce if the incident radiation is of low power None of these To allow for scattering by the sample Because the magnitude of the output signal is proportional to the power of the incident radiation Because the sample won't fluoresce if the incident radiation is of low power ANSWER DOWNLOAD EXAMIANS APP
UV Luminance Spectroscopy What is the relationship between wavelength and wave number? Wavenumber = 1 / wavelength in centimeters Wavelength in nanometers x wavenumber = 1 None of these Wavenumber - wavelength in nanometers = 1 Wavenumber = 1 / wavelength in centimeters Wavelength in nanometers x wavenumber = 1 None of these Wavenumber - wavelength in nanometers = 1 ANSWER DOWNLOAD EXAMIANS APP
UV Luminance Spectroscopy Fluorescence occurs when a molecule lowers its vibrational energy by losing it's excess energy as a photon a molecule returns to the electronic ground state from an excited triplet state by losing it's excess energy as a photon a molecule returns to the electronic ground state from an excited singlet state by losing it's excess energy as a photon None of these a molecule lowers its vibrational energy by losing it's excess energy as a photon a molecule returns to the electronic ground state from an excited triplet state by losing it's excess energy as a photon a molecule returns to the electronic ground state from an excited singlet state by losing it's excess energy as a photon None of these ANSWER DOWNLOAD EXAMIANS APP
UV Luminance Spectroscopy In the intersystem crossing a molecule converts its excess energy to light, and emits a photon All of these the spin of an excited electron reverses, changing the state of the molecule (from singlet state to triplet state or vice versa) a molecule converts excess electronic energy to vibrational energy a molecule converts its excess energy to light, and emits a photon All of these the spin of an excited electron reverses, changing the state of the molecule (from singlet state to triplet state or vice versa) a molecule converts excess electronic energy to vibrational energy ANSWER DOWNLOAD EXAMIANS APP
UV Luminance Spectroscopy Why phosphorescence measurements are usually made at a low temperature? To increase the efficiency of the detector To decease the efficiency of detector To promote phosphorescence by slowing the rate of radiationless transfer processes To prevent thermal degradation of the phosphorescent species To increase the efficiency of the detector To decease the efficiency of detector To promote phosphorescence by slowing the rate of radiationless transfer processes To prevent thermal degradation of the phosphorescent species ANSWER DOWNLOAD EXAMIANS APP
UV Luminance Spectroscopy Why do fluorescence spectrometers often use double-beam optics? All of these To compensate for beam attenuation by the monochromator To compensate for power fluctuations in the radiation source So a reference solution can be used All of these To compensate for beam attenuation by the monochromator To compensate for power fluctuations in the radiation source So a reference solution can be used ANSWER DOWNLOAD EXAMIANS APP
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