EXAM 1
is now available
is now available
Exam 1 answers will be posted on 25-Jan-18.
Assigned: 19-Jan-18
1st Due Date: 24-Jan-18
2nd Due Date: 27-Jan-18
The first iteration of the exam is due 24-Jan-18. The answers will be posted on 25-Jan-18. Any incorrect answers can be resubmitted by 27-Jan-18. Changed answers will be worth 50 % of the original grade. For the 2nd resubmission the work related to the changes must be shown. Please post all questions to the blog.
There will be an in class meeting on the quiz on Friday 19 January and Monday 22 January. This quiz covers:
Lecture 1: Introduction, Chart of the Nuclides
Lecture 2: Nuclear Properties
Lecture 3: Decay Kinetics
Lecture 4: Alpha Decay
Lecture 5: Beta Decay
Use lecture notes, textbooks, Chart of the Nuclides, Table of the Isotopes, and web pages. Use the chart of the nuclides as your primary dataset for isotope half-life. Show your work or references on a separate page and save electronically. Please use 3 significant digits for your answers
Please post any questions on Exam 1 to the blog. Office hours for Exam 1 are Monday at 1200 inn Bagley 303A. Other office hours can be arranged as needed.
ReplyDeleteI have submitted exam 1 by email
ReplyDeleteExam 1 submitted!
ReplyDeleteYou mention showing our work or references and submitting electronically. Do we need to submit scratch work and reference citations for the first iteration as well as the second?
ReplyDeletePlease only submit work for the 2nd submission for any questions changed. For the 1st submission the work is not needed.
DeleteAlso, there at least 2 errors in the Berkeley picture. Do you require us to describe only one of them for credit?
ReplyDeleteI only expected one error. However you can describe both for completeness.
DeleteI can hold a Canvas Conference tonight at 8 PM to answer any test questions. Please let me know if there is an interest.
ReplyDeleteInterested!How does it work?
DeleteFor question 6.2, does it mean we should start with the mass of RA-225 we obtained in 6.1 and do calculation on the decay (beta/alpha) to obtain the masses?
ReplyDeleteThe input for the program is either atoms or activity. If you enter the total 225Ra atoms at time 0, you will get the atoms of all the daughters at the selected times. If you know the number of atoms, you can calculate the mass.
DeleteIf you enter 225Ra activity, you will get the activity of the daughters. Using the equation
DeleteA=(decay constant)*N
allows you to solve for N, the number of atoms for an isotope. If you know the number of atoms of an isotope then you can find the mass.
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DeleteFor question 1, what exactly do you mean by "element with highest density"? If we substitute the radius equation into the density equation, we find that the density of the nucleus does not depend on the mass number A, so all nuclei theoretically have the same density. So...what am I supposed to do here?
ReplyDeleteWhich element on the periodic table has the highest density.
DeleteSo atomic density then? Not nuclear density?
Deleteyes, sorry I should have been clearer on this. The idea is to compare the density of a nuclear with the density of an element.
DeleteAwesome thank you!
DeleteAlso, should answers in the table for 6.2 be in mass units of grams?
ReplyDeleteYes, you can default to grams
DeleteExam 1 was submitted via email yesterday.
ReplyDeleteSubmitted Midterm 1 via email.
ReplyDeleteI have submitted exam 1 both by email and through canvas, as insurance.
ReplyDeleteExam 1 submitted. That was fun
ReplyDeleteMany thanks for the exams and comment. The answers to the first celebration of learning will be posted on Thursday.
ReplyDeleteThis comment has been removed by the author.
ReplyDeleteExam 1 completed and submitted on canvas
ReplyDeleteExam 1 submitted via email.
ReplyDeleteExam 1 submitted via email.
ReplyDeleteExam 1 submitted through canvas
ReplyDeleteExam 1 submitted through Canvas upload.
ReplyDeleteExam submitted via email and on canvas. I couldn't get a lot of the boxes to populate in the PDF so I sent the answers in the email and in the comments on canvas as well.
ReplyDeleteThanks for the information.
Deleteexam submitted via canvas.
ReplyDeleteExam 1 submitted.
ReplyDeleteExam submitted
ReplyDeleteoh i did not know I was supposed to comment on here as well after submitting the exam.
ReplyDeleteI found that some of my answers were pretty close to the model answer but not exactly the same. Probably because I took different significant digits when I was calculating. Will I still get points for that?
ReplyDeleteIt is expected that the calculations will be close but not exact. For example in converting time I use 365.24 days per year. If one used 365 days per year the answers will slightly differ.
DeleteFor question 8.3, the answer key says that it is both Fermi and Gamow-Teller. I had been under the impression that it was either one or the other. Could you please explain why?
ReplyDeleteAlso in Lecture 2 you talk about the concept of nuclear shells, and how magic numbers correspond to filled nuclear shells. Why then does the answer key state that nucleons do not occupy shells? What am I missing?
DeleteProfessor, your answer in 4 to the purpose of the liquid-drop model makes a statement about "the shell model". If this isn't a typo, and "the shell model" is another name for the liquid-drop model, why wouldn't the model use the concept of nucleons in shells?
Deletethe shell model and liquid drop models are different. The liquid drop model shows limitations, which is one of the reasons the shell model was investigated.
DeleteProfessor, the link you provided for referencing the density of a neutron star listed multiple values, including yours of 7E14 and mine of 2.4E14. Is this something I will have to correct for resubmission? If so, do I simply mention which reference I used? Why would one reference be more correct than another, in this case?
ReplyDeleteboth numbers will work. If you reference your source that is sufficient.
DeleteAlso, in using the ERG Nuclide Tool to calculate values for 6.2, the graph data told me the mass of At-217 and Po-213 were always 0g at the measured times, which seemed consistent with their respective millisecond and microsecond half-lives. I checked the tabulated data, but didn't trust it because it gave non-zero mass values for Ra-225 decay products on day 0. I can't think of any way to calculate and justify fixing my answers for these 0 values in my table.
ReplyDeleteYes,some of the values at time 0 do not make sense. The output is a result of the program. You should recognize this, which you did.
DeleteSorry, I know it is late and close to the deadline, but the values I got out of ERG did not give me the correct answers. I suspect I was using the tool wrong, because I got 0's for all times for Bismuth, and did not get 0's for all compounds at t=0. I was wondering if anyone would send me the values they got from ERG so I can work up the correct data? I'm sure my method is correct. I have a mac so I can't use the program on my computer to retry to get new data, I had used a friend's computer the first time!
ReplyDeleteThanks again!
-Sarah
these comments are noted if there are any issues.
DeleteI have sent in my second submission of exam 1 by email, along with the reasoning for my corrections.
ReplyDeleteExam re-submitted!
ReplyDeleteThank you
-Sarah
Submitted second submission.
ReplyDeleteThanks for the comments and submission.
ReplyDelete