The photoelectric effect refers to the ejection of electrons from a material when the material absorbs electromagnetic radiation of sufficient energy. As the frequency of electromagnetic radiation increases, what happens to the kinetic energy of ejected electrons?

Question

The photoelectric effect refers to the ejection of electrons from a material when the material absorbs electromagnetic radiation of sufficient energy.  As the frequency of electromagnetic radiation increases, what happens to the kinetic energy of ejected electrons?

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11ecba2d_1319_1c2b_a3bf_b714d3628a83_MD0008_00 The photoelectric effect describes the ejection of electrons from a substance due to the absorption of electromagnetic radiation. Although higher-intensity electromagnetic radiation exhibits greater electric field oscillations, some types of electromagnetic radiation do not cause the ejection of electrons in any case, regardless of intensity. This is due to the electric potential energy between positive charges (protons) and negative charges (electrons). For each electron there exists a discrete value of electric potential known as the work function (W), and the magnitude of energy absorbed through electromagnetic radiation must exceed W for the ejection of an electron to occur. The energy of electromagnetic radiation (E) is proportional to its frequency (f) via Planck's constant (h = 6.62 × 10⁻³⁴ m²∙kg/s), as given by: 11ecba2d_1319_1c2c_a3bf_1d8e23346807_MD0008_00 Accordingly, the ejection of an electron from a surface by incident electromagnetic radiation depends on the frequency of incident electromagnetic radiation. Furthermore, the conservation of energy dictates that the energy absorbed by an electron must contribute to either the ejection of the electron (overcoming the work function) or to the kinetic energy of the electron following ejection: 11ecba2d_1319_1c2d_a3bf_874e93e8099b_MD0008_00 Consequently, increasing the energy of electromagnetic radiation (ie, frequency) beyond the value of the work function will increase the kinetic energy of ejected electrons. (Choices A and B) Increasing the energy of electromagnetic radiation must increase the kinetic energy of ejected electrons because the work function of each electron is fixed, and the conservation of energy must be maintained. (Choice D) The kinetic energy of ejected electrons must obey the conservation of energy. Absorbed energy from electromagnetic radiation that does not contribute to surpassing the work function is converted to the kinetic energy of ejected electrons. Educational objective: The photoelectric effect describes the ejection of electrons from a substance due to the absorption of electromagnetic radiation with sufficient energy. Because the energy needed to eject an electron is fixed via its work function, increasing the energy of electromagnetic radiation will increase the kinetic energy of ejected electrons.

The Photoelectric Effect Refers to the Ejection of Electrons from a Material