Energy emitted : 3,0714 J
The photoelectric effect is an electron coming out of a metal because of electromagnetic radiation
One type of electromagnetic radiation is light
Electrons can come out of metal because they absorb electromagnetic energy radiated on metals. There is also kinetic energy released from metal, which is according to the equation:
[tex] \large {\boxed {\bold {E = hf-hfo}}} [/tex]
fo = the threshold frequency of electromagnetic waves
Radiation energy is absorbed by photons
The energy in one photon can be formulated as
[tex] \rm E = h \times f [/tex]
Where
E = energy of light, J
h = Planck's constant (6,626.10⁻³⁴ Js)
f = Frequency of electromagnetic waves, Hz
f = c / λ
c = speed of light
= 3.10⁸
λ = wavelength
We determine the number of mercury atoms (Hg) in 1.4 mg
atomic mass Hg = 200
mass Hg = 1.4 mg = 1.4 .10⁻³g
mol Hg = mass: atomic mass
mol Hg = 1.4.10⁻³ g: 200
mol Hg = 7.10⁻⁶
Number of atoms: mole x Avogadro number
(1 mole = 6.02.10²³ particles)
number of atoms: 7.10⁻⁶ x 6.02.10²³
number of atoms: 4.214 x10¹⁸
Frequency of mercury rays:
f = c: λ
f = 3.10⁸: 254 .10⁻⁹
f = 1.1.10¹⁵
The radiation emitted by 1 mercury atom
E = h. f
E = 6,626.10⁻³⁴. 1.1.10¹⁵
E = 7.2886.10⁻¹⁹ J
So that the total energy
E total = 4,214.10¹⁸ .7.2886.10⁻¹⁹
E total = 3,0714 J
Electromagnetic radiation with wavelength of 745 nm
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The energy of a photon
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The equation E = hf
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the approximate energy of a photon
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