Practice question

Förster Resonance Energy Transfer involves dipole-dipole coupling between donor fluorophore in excited state and acceptor fluorophore in ground state. No photon is emitted and reabsorbed; instead energy transfers non-radiatively through long-range electromagnetic interaction. Efficiency decays with sixth power of distance, making it exquisitely sensitive between 1-10 nm. Spectral overlap between donor emission and acceptor absorption, relative dipole orientation, and distance govern transfer. This non-radiative mechanism distinguishes FRET from radiative trivial transfer and enables detection of molecular proximity and conformational dynamics.