UV Luminance Spectroscopy Fluorescence occurs when 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 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 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 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 All of these Because a change in dipole moment lowers the energy required for electronic transitions 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 All of these Because a change in dipole moment lowers the energy required for electronic transitions ANSWER DOWNLOAD EXAMIANS APP
UV Luminance Spectroscopy Why do fluorescence spectrometers often use double-beam optics? All of these To compensate for power fluctuations in the radiation source So a reference solution can be used To compensate for beam attenuation by the monochromator All of these To compensate for power fluctuations in the radiation source So a reference solution can be used To compensate for beam attenuation by the monochromator ANSWER DOWNLOAD EXAMIANS APP
UV Luminance Spectroscopy What is the relationship between wavelength and wave number? 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 Wavenumber - wavelength in nanometers = 1 Wavenumber = 1 / wavelength in centimeters ANSWER DOWNLOAD EXAMIANS APP
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 sample won't fluoresce if the incident radiation is of low power Because the magnitude of the output signal is proportional to the power of the incident radiation None of these To allow for scattering by the sample Because the sample won't fluoresce if the incident radiation is of low power Because the magnitude of the output signal is proportional to the power of the incident radiation ANSWER DOWNLOAD EXAMIANS APP
UV Luminance Spectroscopy Why phosphorescence measurements are usually made at a low temperature? To promote phosphorescence by slowing the rate of radiationless transfer processes To increase the efficiency of the detector To decease the efficiency of detector To prevent thermal degradation of the phosphorescent species To promote phosphorescence by slowing the rate of radiationless transfer processes To increase the efficiency of the detector To decease the efficiency of detector To prevent thermal degradation of the phosphorescent species ANSWER DOWNLOAD EXAMIANS APP
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