WorksheetsQUIZ 1
Total questions: 11
Worksheet time: 6mins
What happens when a molecule absorbs UV/Vis radiation?
It emits radiation immediately
It is excited to a higher energy level
It becomes diamagnetic
It undergoes chemical decomposition
Which state has paired electron spins and is diamagnetic?
Triplet state
Doublet state
Singlet state
Free radical state
What is the main difference between fluorescence and phosphorescence?
Fluorescence involves singlet–singlet transitions, phosphorescence involves triplet–singlet transitions
Fluorescence has longer lifetime than phosphorescence
Phosphorescence occurs at shorter wavelengths than fluorescence
Both occur with the same lifetime
In a Jablonski diagram, the lowest horizontal line represents:
Excited singlet state (S₁)
Excited triplet state (T₁)
Ground state (S₀)
Vibrational relaxation
Which of the following is a radiationless deactivation process?
Fluorescence
Phosphorescence
Internal conversion
Emission spectrum
Fluorescence emission is always observed at:
Shorter wavelength than excitation
Longer wavelength than excitation
Equal wavelength as excitation
Random wavelength independent of excitation
The relationship F = Kc is valid at:
High concentrations only
Low concentrations only
All concentrations
Zero concentration
Which factor generally reduces fluorescence efficiency?
Low temperature
High viscosity solvent
Increased molecular collisions
Addition of electron donor groups (–OH, –NH₂)
What is the role of a photomultiplier tube in a fluorescence spectrometer?
Excitation source
Sample holder
Detector of emitted light
Wavelength selector
Which of the following species is commonly analyzed by fluorescence spectrometry?
Organic enzymes and vitamins
Nitrogen gas
Noble gases
All inorganic ions equally
First code: What number after one?
(a)
