1. QUESTION:
Shown below is a diagram illustrating Rutherford’s alpha scattering experiment. Alpha particles are represented by red circles. Which of the three labeled alpha particles (A, B, or C) will have the most typical trajectory?
SCRIPT:
Shown below is a diagram illustrating Rutherford’s alpha scattering experiment. Alpha particles are represented by red circles. Which of the three labeled alpha particles (A, B, or C) will have the most typical trajectory?
PAUSE
In Rutherford’s experiment, alpha particles are fired at very thin piece of gold foil.
Most of the alpha particles went through the foil with very minor deflection, just like choice B
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The correct answer is choice B.
Let’s see what happens to choice C.
Since alpha particles are positively charged, when they pass close to a nucleus, they would be repelled and deflected at large angles. Like this…
In choice A, we have a head-on collision between the alpha particle and the nucleus. Strong repulsions lead to backscattering of the alpha particle.
Only a very,very small fraction of trajectories similar to choices A and C were observed in Rutherford’s experiment.
This suggested that the distances between nuclei are very very large compared.
to the size of the nuclei.
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2. Video ID: © 2008, Project VALUE (Video Assessment Library for Undergraduate Education), Department of Physical Sciences Nicholls State University Author: Glenn V. Lo Narrator: Funded by Louisiana Board of Regents Contract No. LA-DL-SELECT-13-07/08