Explore BrainMass

Explore BrainMass

    Photoelectric effect and energy of ejected electrons

    Not what you're looking for? Search our solutions OR ask your own Custom question.

    This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here!

    The work function of an element is the energy required to remove an electron from the surface of the solid. The work function for cadmium is 378.2 kJ/mol (that is, it takes 378.2 kJ of energy to remove 1 mol of electrons from 1 mol of Cd atoms on the surface of a sample of cadmium.) What is the maximum wavelength of light that can remove an electron from an atom in cadmium? (ans in nm.)
    Answer is 3.163E+02 nm
    Part 2 of the question is :
    If solid cadmium is irradiated with 217-nm light, what is the maximum kinetic energy that a released electron can have? (ans in J.)

    Could you please solve the second part

    © BrainMass Inc. brainmass.com December 24, 2021, 4:48 pm ad1c9bdddf
    https://brainmass.com/physics/photons/photoelectric-effect-and-energy-ejected-electrons-8878

    SOLUTION This solution is FREE courtesy of BrainMass!

    If we are irradiating a sample with some radiation, it will absorb energy and some of its electrons come out. This is photoelectric effect. If the energy of the incident photon is less than the work function of an atom, then there will not be any ejection of electrons.

    That is there is a min. energy given by hV0 (take v0 as the critical value of the frequency; we also know that wavelength(L) and freq (V) are related as V = C/L)

    V0 is the minimum frequency (or it is the maximum wavelength) which can cause emission of an electron (with zero velocity).

    According to the theory, the excess energy in the photon will appear as the KE of the ejected electron.

    h(v-v0) = KE

    in terms of wavelength, h*C [(1/L)-(1/L0)] = KE

    where h = 6.626*10^-34 Js is the Planks constant and C= 3*10^8 m/s, the velocity of light.

    here L0 = 316.3 nm = 316.3*10^-9 m and the irradiating wavelength is L = 217*10^-9 m

    KE = hC[(1/217*10^-9) - (1/316.3*10^-9)]

    = 6.626 * 10^-34 * 3* 10^8 * 10^9 [0.004608 - 0.0031615]

    = 6.626 * 10^-34 * 3* 10^8 * 10^9 [0.00144673]

    = 19.878 * 10^-34 * 10^17 (0.00144673)

    = 0.0287 * 10^-17 Joule

    This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here!

    © BrainMass Inc. brainmass.com December 24, 2021, 4:48 pm ad1c9bdddf>
    https://brainmass.com/physics/photons/photoelectric-effect-and-energy-ejected-electrons-8878

    ADVERTISEMENT