[ RadSafe ] Flawed Test Questions.....Calling all teachers/profs

Thompson, Dewey L DThompson3 at ameren.com
Tue Apr 9 15:49:55 CDT 2013

Mmmmmmmmm.  I see your point.  Although, as someone who has taught this material (and written exam questions on the subject), I'm less irritated by the questions than you (and apparently) some of the repliers.  (In fact, I was somewhat impressed by the second question).

Question 1.  Which of the following is likely to be induced by bombarding a nucleus with foreign particles?  The point is bombarding a nucleus AND the word "likely".  EMF is an obvious rabbit, so scratch it.  Bombarding means it isn't natural, so c is rabbit 2.  Fusion is much less likely than transmutation, so e is rabbit 3.  THAT should leave you with two choices, which is the game of the 
"best answer game".  Gamma emission is probably emitted with "most" transmutations, and maybe some that don't transmute (if you REALLY REALLY want to prosecute the question, this would be the avenue, as "d" might just be a better technical answer than b), however I would choose b as the best answer.  If you are bombarding nuclei, you are attempting artificial transmutation, and that is the most direct line of sight link to the question. 

Question 7.  Which of the following is an isotope of 13355 Cs ?  The point here is the word isotope.  Now, the rabbit in this question is subtle.  It is the number.  We all know that normal decay moves the A number one or two steps, four it is alpha, SO if you are focusing on the number, you will gravitate to number closest to 13355.  And I'm willing to bet a lot of experienced physicists will bite on b.   

HOWEVER, b) makes no sense, as iodine can't be an isotope of Cs.  SO.  You have to come back to the word isotope.  That means there is only one clear choice, and that HAS to be c), no matter how many neutrons that Cs atom has.............(Hey, it is obviously a universe in a parallel dimension where the laws of physics as we know it don't apply).  

You are correct, grammatically saying that something is an isotope of 13355 Cs is a bit of a non sequitur.  BUT the question author could not simply say "which is an isotope of Cs".................

Reminds me of a question I once wrote "Pandemonium 125 decays by electron capture..................."

For what it's worth


-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu [mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Jake Hecla
Sent: Wednesday, April 03, 2013 2:17 PM
To: The International Radiation Protection (Health Physics) Mailing List
Subject: [ RadSafe ] Flawed Test Questions.....Calling all teachers/profs

Hello Radsafe- I am a student interested in nuclear physics, and I am in a bit of a conundrum regarding a test I recently took that I believe has fundamentally flawed questions. While I realize this isn't a board to turn to for help in schooling, I am concerned the writer of these AP Physics practice tests (not my teacher, they're from an online teacher resource
site) has no idea what he's doing, and is severely screwing up our education. I am looking for people ( teachers/professors especially) who have a bit more experience here to review these questions and let me know if you see the same flaws that I do. I have attached photos of the questions as proof, but I'm typing them out to make them easy to read.


1.  Which of the following is likely to be induced by bombarding a nucleus with foreign particles?

a)      an EMF

b)      an artificial transmutation

c)       a natural transmutation

d)      a gamma emission

e)      a fusion reaction

-If I'm not mistaken, doesn't it vary based on the particle, the energy and the nucleus? For example, if the target was tritium and you bombarded it with deuterium, wouldn't you expect a fusion reaction rather than a "transmutation?" Conversely, if it was a heavier nucleus prone to absorbing a neutron, wouldn't it then be more likely to be a transmutation?

7. Which of the following is an isotope of 13355 Cs ?

a)      12354Xe

b)      13353I

c)       13555Cs

d)      17087Fr

e)      21186Rn

-I believe this question is fundamentally flawed. How can you have an isotope of a given isotope?

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