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Old exams

Here you find problems and solutions to all exams and complementary tests that have been given in the course EG2050 as well as some exams for the older course 2C1118, which had a similar content.

Lärare Mikael Amelin skapade sidan 19 december 2012

Lärare Mikael Amelin ändrade rättigheterna 19 december 2012

Kan därmed läsas av alla och ändras av lärare.
kommenterade 8 mars 2013

Appears to be some bad "translation errors" in the the old exams....
For example 2012-06-13:
problem 3a) " the frequency in area A is 49.94 Hz. What is the frequency in area A at this occasion?" [Swedish versions ask for area D]
Problem 5  "installed capacity (800 kW)" [Answer calculates with 900KW (as stated in swedish version]

The answer for 4b in both English and swedish version is also incosistent with the question (the indexes are wrong//not consistent with flow according to picture)

I really hope that this will not be the case for our exam and it would be nice if all errors of earlier exams are reported here as fast as possible (maybe we can help each other).

Considering the statement today that students are not allowed to make errors at the exam I think the quality control of the old exams & answers are unaccepable, 

(I also wonder if we will get both swedish and english version of the exam since the swedish one appears to be more correct...)

Anmäl missbruk
kommenterade 9 mars 2013

I agree with Henrik. There are lots and lots of errors in the answers provided with the old exams. How are we supposed to get it right if even the teachers/assistants can't answer correctly? Besides, the level of difficulty on the exam questions greatly exceed that of those in the compendium, which means that we have to practice on these "new" problems with an answer sheet that is inadequate at best.

Regarding the errors in the exam from 2012-06-13, I am fairly convinced that the solution to Problem 7 is wrong as well ("Acceptera bud 1, 3, 7, 8").

Anmäl missbruk
Lärare kommenterade 10 mars 2013

Thank you for pointing out errors in the old exams. The English exam from 13 June 2012 is in fact a draft version, which should have been replaced by the final version. The errors in the problem texts were detected by the teacher who was managing the exam and did not affect the exam.

While checking your comments, I also realised that the solutions to part II have not yet been translated into English. Unfortunately, I will not have time to do this before the exam on 14 March; English-speaking students will have to practice on the other old exams or ask a Swedish-speaking friend for help.

Perhaps the repetition lecture was slightly unclear concerning mistakes. Of course students are allowed to make mistakes---it is sufficient to get 33 points out 40 in part I to pass the exam. The point in the lecture was that some students consider this as a very high requirement, whereas I think it is quite generous.

In problem 4b of the exam 13 June 2012, the solution incorrectly included the future generation in power plant 4 in the value of water stored in reservoir 2. This would have resultet in the score being reduced by 2 points. Hence, the teacher would have obtained 38 points in part I and would still have passed the exam.

In problem 7, the correct answer is to accept bids 1, 3, 6 and 7, which is clear from the reasoning in the solution. The errors only appear in the summary in the last paragraph. In an exam, this would normally only result in a question mark, but no score reduction.

Finally, if you have detected lots and lots of errors, it would be helpful if you could inform us about them in order to let us correct them.

Anmäl missbruk
kommenterade 10 mars 2013

Hi,

Thanks for clearing that out. Since I need to study some new types of problems for the exam, I don't have the time to go back and point out every single one of the errors I have found, but I can give you three examples on some of the most recent errors I encountered. All of these might be considered as "minor" errors, but my concern is that when some of these errors appears in the exam question (like in the last two of my examples below), students like me tend to get stressed and waste a lot of time and energy thinking in the lines of "is this an error or do I somehow misinterpret this question?"

- On question 4 in one of the exams (can't remember which one right now), the index of "lambda" for the future price is wrong.

- On the exam from 2010.06.09, question 2: The table states the electricity consumption between January 1 and April 30 (as well as from May 1 to December 31) in "TWh/year". In other words, the table is stating that "Between January 1 and April 30, 55 TWh/year is consumed. And between May 1 and December 31, 110 TWh/year is consumed."

- Exam from 2010.06.09, Swedish version, question 6: Här exporteras en viss mängd el från område Norr till Syd. På tentamen står det "Observera att all el som producenterna matar in i norra delen av landet (alltså även den el som exporteras söderut) erhåller områdespriset för norra Rike. På motsvarande sätt måste alla konsumenter i södra Rike (alltså även de som köper el importerad från Norra Rike) betala områdespriset för södra Rike."

Logiskt sett så bör ju KOSTNADEN för producerad el i Norr gälla för elen som exporteras till Syd. Konsumenterna i Syd betalar sedan PRISET som gäller i Syd för denna el. Problemformuleringen verkar ju dock först säga att PRISET för exporterad el är det som gäller i Norr, för att sedan motsäga denna mening och säga att PRISET är det som råder i Syd. Väldigt förvirrande när man sitter på en tenta och inte vet om frågan är otydligt formulerad eller om man själv förstått något helt fel. I detta fall borde väl rimligtvis "kostnad" stå istället för "pris" när man pratar om elen som produceras i Norr (första meningen)?

Anmäl missbruk
Lärare kommenterade 10 mars 2013

If you are uncertain about an exam question then ask (teachers will come to the exam at least three times).

In the exam 9 June 2010, problem 2, the unit should be TWh.

In the exam 9 June 2010, problem 6b, the explanation that all producers in area North are paid the area price is correct. The cost of generating electricity is not the same as the price that is paid (except for the price-setting unit).

Anmäl missbruk
kommenterade 11 mars 2013

Exam 2011-03-16 Problem 4 a): In the solution, value of stored water for i=2 (Sele) the marginal production equivalent should be gamma2+gamma3+gamma5 (Not gamma4!)

Exam 2011-06-10 Problem 4 e): In the solution the wrong marginal production equivalents and maximal discharges have been calculated. It should be mu1=0.35, mu2=0.3, Qmax1=100, Qmax2=50.


Anmäl missbruk
Lärare kommenterade 11 mars 2013

Exam 16 March 2011, problem 4a: No the solution is correct. Water from Sele (i = 2) will eventually pass Fallet (i = 4) and then to By (i = 5).

Exam 10 June 2011, problem 4e: Yes, there is a printing error in the English version.

Anmäl missbruk
kommenterade 11 mars 2013

Oh my misstake, I mixed up the indexing. Moreover, I noticed that in Problem 7 exam 2011-06-10 the price interval for block bid 2 says 600 in the english version, and 620 in the swedish version. So I guess this should be corrected in the english version since otherwise it will change our conclusion.  

Anmäl missbruk
Lärare kommenterade 11 mars 2013

Exam 10 June 2011, problem 7: Yes, the price of block bid 2 should be 620, otherwise the solution becomes more difficult than intended.

Anmäl missbruk
kommenterade 12 mars 2013

Compl exam 28 june 2012 problem 2c:

c) (2 p) Assume that the electricity price during one hour is 200¤/MWh and in the next hour it is 220¤/MWh. Possible explanations are that I) The hydro reservoirs are full at the end of the first hour, II) The hydro reservoirs are empty at the end of the first hour, III) The hydro power generates installed capacity during the second hour.

Solutions states: 4. I and III are true but not II.

I read the question as you shold state reasons for the price being higher in hour 2 and not actions that should be taken since producer knows higher price in hour2 before producing in hour 1?

Anmäl missbruk

Syed Mushfiqur Rahaman taggade med systw. 9 oktober 2014