The silicon wafer is coated with a layer of metallic aluminum which acts as an electrical contact. The x-ray diffraction pattern of aluminum is measured in a diffractometer with Fe Kα radiation. At what angle, θ, do you expect to observe the first reflection of aluminum, i.e., the reflection at the lowest angle? Express your answer in degrees.
Posted by Writeacher on Friday, January 11, 2013 at 8:48am.
anang, John, Prya, Sergey, Dylanprof, Amelia, kkr, kiril, Lena, c ~
Dumping ALL your homework questions in any one place (such as this website) is considered spamming. I've removed your collective 50+ posts except for those which received responses.
Do not do this again.
you should try to do your work instead of just posting it and expecting answers. you can ask for help or ask for someone to check your answers but its irritating and uncalled for to keep posting question after question after question.
You stupid person.
If someone has a lot of legitimate questions, they have a lot of questions.
It is not spamming at all, it is asking for help.
This website is about answering questions. If someone has a lot of questions, you should try and answer them, not delete their questions.
What kind of idiotic logic is that? "Your contributions to this website were removed because there were too many."
Please, stop harassing people who are genuinely asking for help. It is what this website is for. Being inquisitive is fine.
13.8
They shouldn't be answered as they are questions from a current online exam.
+1! you have right!
Stop cheat!
What's the answer?
To determine the angle at which the first reflection of aluminum occurs, we need to use the principles of X-ray diffraction. The equation that relates the angle of diffraction (θ) with the wavelength (λ) and the spacing between the atomic planes (d) is known as Bragg's Law:
n * λ = 2 * d * sin(θ)
In this case, we are given that the X-ray radiation used is Fe Kα, which corresponds to a wavelength of 1.937 Å (angstroms). The atomic spacing (d) for aluminum can be looked up in tables or calculated using the Miller indices of the crystal planes.
The first reflection corresponds to n = 1, so we can rearrange Bragg's Law to solve for the angle θ:
θ = arcsin((n * λ) / (2 * d))
Now, to calculate the angle for the first reflection of aluminum, we need the atomic spacing (d) for the relevant crystal plane. For aluminum, the Miller indices for the (111) plane can be used, and the corresponding d value is approximately 2.057 Å.
Substituting the values into the equation:
θ = arcsin((1 * 1.937 Å) / (2 * 2.057 Å))
θ = arcsin(0.471)
Using a scientific calculator or trigonometric tables, the angle θ is approximately 28.2 degrees.
Therefore, we expect to observe the first reflection of aluminum at an angle of approximately 28.2 degrees.