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

$\overline{){\mathbf{\u2206}}{\mathbf{E}}{\mathbf{=}}{{\mathbf{E}}}_{\mathbf{w}\mathbf{o}\mathbf{r}\mathbf{k}\mathbf{}\mathbf{f}\mathbf{u}\mathbf{n}\mathbf{c}\mathbf{t}\mathbf{i}\mathbf{o}\mathbf{n}}{\mathbf{+}}{{\mathbf{E}}}_{\mathbf{K}\mathbf{E}\mathbf{}\mathbf{o}\mathbf{f}\mathbf{}\mathbf{e}\mathbf{l}\mathbf{e}\mathbf{c}\mathbf{t}\mathbf{r}\mathbf{o}\mathbf{n}}}$

**Where:**

• **Δ****E **is* the** total energy or the energy of the light/photon/radiation* and can be calculated using the equation:

$\overline{)\mathbf{E}\mathbf{=}\frac{\mathbf{hc}}{\mathbf{\lambda}}}$

E_{total energy} = J

h = Planck’s constant = 6.626x10^{-34} J∙s

λ = wavelength = m

↑ ΔE → ↓ λ

• **E _{work function} **is

• **E _{kinetic energy}** is the

$\overline{){{\mathbf{E}}}_{\mathbf{k}\mathbf{i}\mathbf{n}\mathbf{e}\mathbf{t}\mathbf{i}\mathbf{c}\mathbf{}\mathbf{e}\mathbf{n}\mathbf{e}\mathbf{r}\mathbf{g}\mathbf{y}}{\mathbf{=}}\frac{\mathbf{1}}{\mathbf{2}}{\mathbf{m}}{{\mathbf{v}}}^{{\mathbf{2}}}}$

E_{kinetic 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

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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