UV Luminance Spectroscopy Why must the radiation source for fluorescence spectrometry be more powerful than for absorption spectroscopy? 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 To allow for scattering by the sample None of these 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 To allow for scattering by the sample None of these 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
UV Luminance Spectroscopy Internal conversion is where A molecule converts its excess energy to light, and emits a photon the spin of an excited electron reverses, changing the state of the molecule (from singlet state to triplet state or vice versa) None of these A molecule converts excess electronic energy to vibrational energy A molecule converts its excess energy to light, and emits a photon the spin of an excited electron reverses, changing the state of the molecule (from singlet state to triplet state or vice versa) None of these A molecule converts excess electronic energy to vibrational energy ANSWER DOWNLOAD EXAMIANS APP
UV Luminance Spectroscopy For a molecule to absorb IR, why must the molecule's vibrations cause fluctuations in the dipole moment of the molecule? Because a change in dipole moment lowers the energy required for electronic transitions All of these Because for absorption to occur, the radiation must interact with the electric field caused by changing dipole moment Because fluctuations in the dipole moment allow the molecule to deform by bending and stretching Because a change in dipole moment lowers the energy required for electronic transitions All of these Because for absorption to occur, the radiation must interact with the electric field caused by changing dipole moment Because fluctuations in the dipole moment allow the molecule to deform by bending and stretching ANSWER DOWNLOAD EXAMIANS APP
UV Luminance Spectroscopy What is the relationship between wavelength and wave number? Wavenumber - wavelength in nanometers = 1 Wavenumber = 1 / wavelength in centimeters None of these Wavelength in nanometers x wavenumber = 1 Wavenumber - wavelength in nanometers = 1 Wavenumber = 1 / wavelength in centimeters None of these Wavelength in nanometers x wavenumber = 1 ANSWER DOWNLOAD EXAMIANS APP
UV Luminance Spectroscopy Why phosphorescence measurements are usually made at a low temperature? 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 To increase the efficiency of the detector ANSWER DOWNLOAD EXAMIANS APP
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