Problem: Light from three different lasers (A, B, and C), each with a different wavelength, was shined onto the same metal surface. Laser A produced no photoelectrons. Lasers B and C both produced photoelectrons, but the photoelectrons produced by laser B had a greater velocity than those produced by laser C. Arrange the lasers in order of increasing wavelength.

FREE Expert Solution

Total energy (ΔE) in photoelectric effect can be calculated using the following equation:

E=Ework function+EKE of electron


Where:

Δis the total energy or the energy of the light/photon/radiation and can be calculated using the equation:

E=hcλ

Etotal energy = J
h = Planck’s constant = 6.626x10-34 Js
λ = wavelength = m

 ↑ ΔE → ↓ λ

Ework function is the work function or threshold frequency of the metal (minimum energy required to remove an electron from the metal)

Ekinetic energy is the kinetic energy of the ejected electron and can be calculated using the equation:

Ekinetic energy=12mv2

Ekinetic energy = J
m = mass of e- = 9.11x10-31 kg   (can be found in books or the internet)
v = velocity of the e- = m/s

↑ velocity → ↑ kinetic energy

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Problem Details

Light from three different lasers (A, B, and C), each with a different wavelength, was shined onto the same metal surface. Laser A produced no photoelectrons. Lasers B and C both produced photoelectrons, but the photoelectrons produced by laser B had a greater velocity than those produced by laser C. Arrange the lasers in order of increasing wavelength.

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