Beryllium on leaf of a plant
About points...
We associate a certain number of points with each exercise.
When you click an exercise into a collection, this number will be taken as points for the exercise, kind of "by default".
But once the exercise is on the collection, you can edit the number of points for the exercise in the collection independently, without any effect on "points by default" as represented by the number here.
That being said... How many "default points" should you associate with an exercise upon creation?
As with difficulty, there is no straight forward and generally accepted way.
But as a guideline, we tend to give as many points by default as there are mathematical steps to do in the exercise.
Again, very vague... But the number should kind of represent the "work" required.
When you click an exercise into a collection, this number will be taken as points for the exercise, kind of "by default".
But once the exercise is on the collection, you can edit the number of points for the exercise in the collection independently, without any effect on "points by default" as represented by the number here.
That being said... How many "default points" should you associate with an exercise upon creation?
As with difficulty, there is no straight forward and generally accepted way.
But as a guideline, we tend to give as many points by default as there are mathematical steps to do in the exercise.
Again, very vague... But the number should kind of represent the "work" required.
About difficulty...
We associate a certain difficulty with each exercise.
When you click an exercise into a collection, this number will be taken as difficulty for the exercise, kind of "by default".
But once the exercise is on the collection, you can edit its difficulty in the collection independently, without any effect on the "difficulty by default" here.
Why we use chess pieces? Well... we like chess, we like playing around with \(\LaTeX\)-fonts, we wanted symbols that need less space than six stars in a table-column... But in your layouts, you are of course free to indicate the difficulty of the exercise the way you want.
That being said... How "difficult" is an exercise? It depends on many factors, like what was being taught etc.
In physics exercises, we try to follow this pattern:
Level 1 - One formula (one you would find in a reference book) is enough to solve the exercise. Example exercise
Level 2 - Two formulas are needed, it's possible to compute an "in-between" solution, i.e. no algebraic equation needed. Example exercise
Level 3 - "Chain-computations" like on level 2, but 3+ calculations. Still, no equations, i.e. you are not forced to solve it in an algebraic manner. Example exercise
Level 4 - Exercise needs to be solved by algebraic equations, not possible to calculate numerical "in-between" results. Example exercise
Level 5 -
Level 6 -
When you click an exercise into a collection, this number will be taken as difficulty for the exercise, kind of "by default".
But once the exercise is on the collection, you can edit its difficulty in the collection independently, without any effect on the "difficulty by default" here.
Why we use chess pieces? Well... we like chess, we like playing around with \(\LaTeX\)-fonts, we wanted symbols that need less space than six stars in a table-column... But in your layouts, you are of course free to indicate the difficulty of the exercise the way you want.
That being said... How "difficult" is an exercise? It depends on many factors, like what was being taught etc.
In physics exercises, we try to follow this pattern:
Level 1 - One formula (one you would find in a reference book) is enough to solve the exercise. Example exercise
Level 2 - Two formulas are needed, it's possible to compute an "in-between" solution, i.e. no algebraic equation needed. Example exercise
Level 3 - "Chain-computations" like on level 2, but 3+ calculations. Still, no equations, i.e. you are not forced to solve it in an algebraic manner. Example exercise
Level 4 - Exercise needs to be solved by algebraic equations, not possible to calculate numerical "in-between" results. Example exercise
Level 5 -
Level 6 -
Question
Solution
Short
Video
\(\LaTeX\)
Need help? Yes, please!
The following quantities appear in the problem:
Masse \(m\) / Aktivität \(A\) / molare Masse \(M\) / Stoffmenge \(n\) / Halbwertszeit \(T\) / Zerfallskonstante \(\lambda\) / Anzahl \(N\) /
The following formulas must be used to solve the exercise:
\(A = \lambda \cdot N \quad \) \(T = \dfrac{\ln 2}{\lambda} \quad \) \(m = nM \quad \) \(N = n \cdot N_{\rm A} \quad \)
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Exercise:
Beryllium- is produced in the upper atmosphere and filters down onto the Earth's surface. Formelbuch It decays with a half-life of about TO. Estimate the initial mass of isotopeBe on the leaf of a plant if it is detected to have num decays per second.
Solution:
Geg T TO T A A Gesmassmsikg The detected activity of AO means that there are N fracAlambda fracAfracln T fracT Aln fracT Aln fracln AT N n fracNsscNA fracT AlnsscNA n Beryllium- isotopes present on the leaf. Because one of them has meO mass there are m N m_ fracTAln m_ fracT Aln me mb approx mbS on the leaf. Alternatively you can also compute the mass by knowing the molar mass to be MO the calculation then gives: m nM fracTAln sscNA M fracT Aln ncNA M m approx mS m fracT A MlnsscNA fracm_T A ln mS
Beryllium- is produced in the upper atmosphere and filters down onto the Earth's surface. Formelbuch It decays with a half-life of about TO. Estimate the initial mass of isotopeBe on the leaf of a plant if it is detected to have num decays per second.
Solution:
Geg T TO T A A Gesmassmsikg The detected activity of AO means that there are N fracAlambda fracAfracln T fracT Aln fracT Aln fracln AT N n fracNsscNA fracT AlnsscNA n Beryllium- isotopes present on the leaf. Because one of them has meO mass there are m N m_ fracTAln m_ fracT Aln me mb approx mbS on the leaf. Alternatively you can also compute the mass by knowing the molar mass to be MO the calculation then gives: m nM fracTAln sscNA M fracT Aln ncNA M m approx mS m fracT A MlnsscNA fracm_T A ln mS
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Exercise:
Beryllium- is produced in the upper atmosphere and filters down onto the Earth's surface. Formelbuch It decays with a half-life of about TO. Estimate the initial mass of isotopeBe on the leaf of a plant if it is detected to have num decays per second.
Solution:
Geg T TO T A A Gesmassmsikg The detected activity of AO means that there are N fracAlambda fracAfracln T fracT Aln fracT Aln fracln AT N n fracNsscNA fracT AlnsscNA n Beryllium- isotopes present on the leaf. Because one of them has meO mass there are m N m_ fracTAln m_ fracT Aln me mb approx mbS on the leaf. Alternatively you can also compute the mass by knowing the molar mass to be MO the calculation then gives: m nM fracTAln sscNA M fracT Aln ncNA M m approx mS m fracT A MlnsscNA fracm_T A ln mS
Beryllium- is produced in the upper atmosphere and filters down onto the Earth's surface. Formelbuch It decays with a half-life of about TO. Estimate the initial mass of isotopeBe on the leaf of a plant if it is detected to have num decays per second.
Solution:
Geg T TO T A A Gesmassmsikg The detected activity of AO means that there are N fracAlambda fracAfracln T fracT Aln fracT Aln fracln AT N n fracNsscNA fracT AlnsscNA n Beryllium- isotopes present on the leaf. Because one of them has meO mass there are m N m_ fracTAln m_ fracT Aln me mb approx mbS on the leaf. Alternatively you can also compute the mass by knowing the molar mass to be MO the calculation then gives: m nM fracTAln sscNA M fracT Aln ncNA M m approx mS m fracT A MlnsscNA fracm_T A ln mS
Contained in these collections
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Aktivität by uz
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Aktivität und molare Masse by TeXercises
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Radiometrische Datierung by pw
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