light frequency 1.40x10^15 Hz strike a surface causing photoelectrons to leave with a KE of 1.05 eV what is the work function in
1 answer:
Answer:
The Work Function is 4.74eV.
Explanation:
The photoelectric effect is a phenomenon in which a beam of light is projected towards a metal plate and this leads to the ejection of electrons from the metal. The minimum amount of energy required for this ejection of electrons is known as the work function. When the energy of the light beam is less than the work function, then the electrons are not emitted.
The photoelectric effect is represented by the equation:
E = φ + KE where
E = energy of the incident photons
KE = kinetic energy of photoelectrons
φ = Work function of the metal
This can also be written in terms of frequency as:
h = h₀ + mv²
= frequency of the incident light beam
₀ = frequency of the photoelectrons
m = mass of the electron
v = velocity of the electron
h = Plank's constant 6.623 x 10⁻³⁴Js
Conversion factor: 1eV = 1.602 x 10⁻¹⁹ J
So, 1.05eV = 1.682 10⁻¹⁹ J
Using the formulas,
(6.623 x 10⁻³⁴Js)(1.40x10¹⁵ s⁻¹) = φ + 1.682 x 10⁻¹⁹ J
(9.272 x 10⁻¹⁹) - (1.682 x 10⁻¹⁹) = φ
φ = 7.590 x 10⁻¹⁹ J = 4.74 eV
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