Assume the mass of an electron is 9.11 x 10-31 kg.
a. Calculate the wavelength of an electron traveling with a speed of 2.65 x 106 m/s.
b. What would the wavelength of the helium atom be if it were traveling at the same speed as the electron in part a (1 amu = 1.6606 x 10-24 g)?
- Answer a
2.74 x 10-10 m
- Answer b
3.77 x 10-14 m
What is the de Broglie wavelength of a 46 g baseball traveling at 94 mph?
3.43 x 10-34 m
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Which of the following equations describe particle-like behavior? Which describe wavelike behavior?
- \(c = λν\)
- \(E = hν\)
e. describes particle-like behavior
a&d describe wavelike behavior
RGB color television and computer displays use cathode ray tubes that produce colors by mixing red, green, and blue light. If we look at the screen with a magnifying glass, we can see individual dots turn on and off as the colors change. Using a spectrum of visible light, determine the approximate wavelength of each of these colors. What is the frequency and energy of a photon of each of these colors
Red: 660 nm; 4.54 × 1014 Hz; 3.01 × 10−19 J. Green: 520 nm; 5.77 × 1014 Hz; 3.82 × 10−19 J. Blue: 440 nm; 6.81 × 1014 Hz; 4.51 × 10−19 J.
A bright violet line occurs at 435.8 nm in the emission spectrum of mercury vapor. What amount of energy, in joules, must be released by an electron in a mercury atom to produce a photon of this light?
When rubidium ions are heated to a high temperature, two lines are observed in its line spectrum at wavelengths (a) 7.9 × 10−7 m and (b) 4.2 × 10−7 m. What are the frequencies of the two lines? What color do we see when we heat a rubidium compound?
The frequency of (a) would be 3.79 × 1014 s-1.
The frequency of (b) would be 7.13 × 1014 s-1.
Because (a) would be in the near-IR, the compound would appear purple/blue based on the wavelength of (b).
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The emission spectrum of cesium contains two lines whose frequencies are (a) 3.45 × 1014 Hz and (b) 6.53 × 1014 Hz. What are the wavelengths and energies per photon of the two lines? What color are the lines?
- Answer a
λ = 8.69 × 10−7 m; E = 2.29 × 10−19 J; red
- Answer b
λ = 4.59 × 10−7 m; E = 4.33 × 10−19 J; blue
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Contributors and Attributions
Paul Flowers (University of North Carolina - Pembroke), Klaus Theopold (University of Delaware) and Richard Langley (Stephen F. Austin State University) with contributing authors. Textbook content produced by OpenStax College is licensed under a Creative Commons Attribution License 4.0 license. Download for free at http://cnx.org/contents/85abf193-2bd...email@example.com).
- Adelaide Clark, Oregon Institute of Technology
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