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24 electrons can be used to probe the arrangement of atoms on a solid surface if the wavelength of the electrons is comparable with the spacing between the atoms. Which of the following electron velocities would be appropriate for use in this application if the atoms are separated by 0.320 nm?

1) 0.5 x 10⁶ m/s
2) 1.0 x 10⁶ m/s
3) 2.0 x 10⁶ m/s
4) 4.0 x 10⁶ m/s

1 Answer

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Final answer:

To find the correct electron velocity to probe atomic arrangements with a 0.320 nm spacing, we use the de Broglie wavelength formula adjusted for non-relativistic motion. The calculation involves Planck's constant, the mass of an electron, and the desired wavelength, yielding a velocity that should match one of the provided options.

Step-by-step explanation:

Calculating the Appropriate Electron Velocity

To determine the appropriate electron velocity for probing atomic arrangements with a given spacing, we can use the de Broglie wavelength equation, λ = h/p, where λ is the wavelength, h is Planck's constant, and p is the momentum of the electron.

Since we are dealing with non-relativistic velocities (evidenced by the given options), the momentum can be expressed as p = mv where m is the mass of an electron and v is its velocity. Therefore, the de Broglie wavelength equation becomes λ = h/(mv).

We want the electrons to have a wavelength (λ) comparable to the spacing between the atoms (0.320 nm). Substituting the known values and rearranging for velocity (v), we get:

v = h/(mλ)

Where h = 6.626 x 10-34 J⋅s (Planck's constant) and m = 9.109 x 10-31 kg (mass of an electron).

Plugging in λ = 0.320 nm = 0.320 x 10-9 m, we can calculate the approximate velocity that gives us this wavelength. After calculating, we would select from the provided options the velocity that best matches our result, ensuring it is non-relativistic and appropriate for this application.

User Alexandre Demelas
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