Physics Elbx 1. Fluorescent bead (3 pts). In the process of fluorescence, a mole
ID: 2269132 • Letter: P
Question
Physics Elbx 1. Fluorescent bead (3 pts). In the process of fluorescence, a molecule in its ground state will absorb a photon with a certain energy Eex, called the excitation energy, and then emit a photon with energy Eem the emission energy. Obviously, the molecule cannot emit more energy than was absorbed. a) You wrote in your notebook that you excited a fluorescent bead at = 640 nm and found that it fluoresced (emitted) at -520 nm. Or was it the other way around? Do a calculation and see if b) You shine a laser on your bead at the excitation wavelength. The laser has a power of 1 mW. How c) You wish to build a microscope that allows you to excite the bead at its excitation wavelength and those figures should be switched. many photons are emitted by the laser in one second? detect the fluorescence at the emission wavelength. This requires a pair of filters, one that allows transmit?) You may have to look at an electromagnetic spectrum to figure this out. only the excitation wavelength to pass through, and the other that allows only the emission wavelength to pass through. What color will these filters appear (i.e. what color light will theyExplanation / Answer
Incident energy is required to be more than threshold energy for emission of electron. Every molecules/ atoms required some energy to excite to electron and hence release of photon. This excitation energy corresponding to the work function, which is the characteristic of atoms or molecules.
E=hxfrequency
E=C/ wavelength.
Thus more energy and hence more frequency but less wavelength is desirable for photo emission.
Kinetic energy of photo emission is the difference of energy incident - Work function.
Kinetic energy attained only if incident energy is more than work function
The difference of wavelength of 640nm to 520nm is corresponding to work function