Radioactivity taken up by cells
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:
Zeit \(t\) / Zerfallskonstante \(\lambda\) / Anzahl \(N\) / Verhältnis / Anteil \(\eta\) /
The following formulas must be used to solve the exercise:
\(\eta = \dfrac{a}{A} \quad \) \(N_t = N_0 \cdot \text{e}^{-\lambda t} \quad \)
No explanation / solution video to this exercise has yet been created.
Visit our YouTube-Channel to see solutions to other exercises.
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Visit our YouTube-Channel to see solutions to other exercises.
Don't forget to subscribe to our channel, like the videos and leave comments!
Exercise:
In a certain experiment isotopeP half life .d is injected o a medium containing a culture of bacteria. After min the cells are washed and a detector that is % efficient i.e. counts % percent of emitted upbeta rays records counts per minute from all the cells. Calculate the activity of the original Phosphor-source under the asption that the cells took up .% of the Phosphor.
Solution:
boxGegeben T .d .es t min s eta' % . A_d per-modereciprocalperminute .Bq eta .% . boxGesucht textInitial activity A_siBq After min the Phosphor's acitivty within the cells -- since the detector registers only % -- is: A_c fracA_deta' frac.Bq. Bq And because the cells took only .% of the Phosphor up the overall Phosphor's activity including the Phosphor that wasn't taken up by the cells must be: A_t fracA_ceta fracA_deta' eta fracBq. .Bq This activity was min earlier: A_ A_t mathrme^+fracln Tt A_t ^+fractT fracA_deta' eta mathrme^+fracln Tt Bq boxbox A_ fracA_deta' eta mathrme^+fracln Tt Bq
In a certain experiment isotopeP half life .d is injected o a medium containing a culture of bacteria. After min the cells are washed and a detector that is % efficient i.e. counts % percent of emitted upbeta rays records counts per minute from all the cells. Calculate the activity of the original Phosphor-source under the asption that the cells took up .% of the Phosphor.
Solution:
boxGegeben T .d .es t min s eta' % . A_d per-modereciprocalperminute .Bq eta .% . boxGesucht textInitial activity A_siBq After min the Phosphor's acitivty within the cells -- since the detector registers only % -- is: A_c fracA_deta' frac.Bq. Bq And because the cells took only .% of the Phosphor up the overall Phosphor's activity including the Phosphor that wasn't taken up by the cells must be: A_t fracA_ceta fracA_deta' eta fracBq. .Bq This activity was min earlier: A_ A_t mathrme^+fracln Tt A_t ^+fractT fracA_deta' eta mathrme^+fracln Tt Bq boxbox A_ fracA_deta' eta mathrme^+fracln Tt Bq
Meta Information
Exercise:
In a certain experiment isotopeP half life .d is injected o a medium containing a culture of bacteria. After min the cells are washed and a detector that is % efficient i.e. counts % percent of emitted upbeta rays records counts per minute from all the cells. Calculate the activity of the original Phosphor-source under the asption that the cells took up .% of the Phosphor.
Solution:
boxGegeben T .d .es t min s eta' % . A_d per-modereciprocalperminute .Bq eta .% . boxGesucht textInitial activity A_siBq After min the Phosphor's acitivty within the cells -- since the detector registers only % -- is: A_c fracA_deta' frac.Bq. Bq And because the cells took only .% of the Phosphor up the overall Phosphor's activity including the Phosphor that wasn't taken up by the cells must be: A_t fracA_ceta fracA_deta' eta fracBq. .Bq This activity was min earlier: A_ A_t mathrme^+fracln Tt A_t ^+fractT fracA_deta' eta mathrme^+fracln Tt Bq boxbox A_ fracA_deta' eta mathrme^+fracln Tt Bq
In a certain experiment isotopeP half life .d is injected o a medium containing a culture of bacteria. After min the cells are washed and a detector that is % efficient i.e. counts % percent of emitted upbeta rays records counts per minute from all the cells. Calculate the activity of the original Phosphor-source under the asption that the cells took up .% of the Phosphor.
Solution:
boxGegeben T .d .es t min s eta' % . A_d per-modereciprocalperminute .Bq eta .% . boxGesucht textInitial activity A_siBq After min the Phosphor's acitivty within the cells -- since the detector registers only % -- is: A_c fracA_deta' frac.Bq. Bq And because the cells took only .% of the Phosphor up the overall Phosphor's activity including the Phosphor that wasn't taken up by the cells must be: A_t fracA_ceta fracA_deta' eta fracBq. .Bq This activity was min earlier: A_ A_t mathrme^+fracln Tt A_t ^+fractT fracA_deta' eta mathrme^+fracln Tt Bq boxbox A_ fracA_deta' eta mathrme^+fracln Tt Bq
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Radioactivity taken up by cells by TeXercises