Electromagnetic radiation with a frequency of 8.6 ´ 1014 hz incident on an unknown metal surface causes ejection of photoelectrons with kinetic energies of 1.3 ´ 10–19 j. what is the unknown metal?

The unknown metal is Sodium.

Explanation: Photoelectric effect happens when a metal surface is hit by a monochromatic eletromagnetic wave causing the surface to emit electrons, which is the case for question.

To determine the metal, we have to find Φ or work function (W), which is the energy necessary to detach a photoelectron from the surface:

W = hf - KE

where:

h is Planck's constant and equals 6.63. J/s;

f is the frequency of the wave;

KE is kinetic energy the electron has the instant it detaches from the surface;

W = hf - KE

W = 6.63.. 8.6. - 1.3.

W = 57.018. - 1.3.

W = 4.4. eV

The element which uses this amount of energy to detach an electron is Sodium (Na).

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explanation:

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