Milk
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 \(t\) / Masse \(m\) / Energie \(E\) / Aktivität \(A\) / Organdosis \(H\) / Radius \(r\) / Oberfläche \(S\) / Zerfallskonstante \(\lambda\) / Energiedosis \(D\) / Strahlungswichtungsfaktor \(w_R\) /
The following formulas must be used to solve the exercise:
\(D = \dfrac{E}{m} \quad \) \(S = 4 \pi r^2 \quad \) \(A_t = A_0 \cdot \text{e}^{-\lambda t} \quad \) \(H = wD \quad \)
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Exercise:
Ase a liter of milk typically has an activity of pqBq due to the upbeta-emitter isotopeK. If a person drinks two glasses pq.l per day estimate the total effective dose in Sievert received in a year. As a crude model ase the milk stays in the stomach for hours and is then released. Ase also that very roughly % of the pq.MeV released per decay is absorbed by the body. Compare your result to the normal allowed dose of pqmSv. Make your estimate for a pqkg adult.
Solution:
Each decay deposits % of its energy pq.MeV in the body i.e. pq.MeV. Since the source's activity is pqBq its deposited energy is E_ pq.MeV pqBq pq.J pqs^- pq.J/s. In nine hours the body absorbes E_ E_ t pq.J. In a year this is E E_ pq.J. The absorbed energy dose of a pqkg person corresponding to this energy is D fracEm fracpq.Jpqkg pq.Gy. Since isotopeK is a upbeta-emitter both upbeta^+ and upbeta^- occur the q-factor for its radiation is electrons and photons. The equivalent dose hence is H qD pq.Sv. The absorbed dose in a year is pq.upmu Sv and is negligible to pqmSv the normal allowed dose.
Ase a liter of milk typically has an activity of pqBq due to the upbeta-emitter isotopeK. If a person drinks two glasses pq.l per day estimate the total effective dose in Sievert received in a year. As a crude model ase the milk stays in the stomach for hours and is then released. Ase also that very roughly % of the pq.MeV released per decay is absorbed by the body. Compare your result to the normal allowed dose of pqmSv. Make your estimate for a pqkg adult.
Solution:
Each decay deposits % of its energy pq.MeV in the body i.e. pq.MeV. Since the source's activity is pqBq its deposited energy is E_ pq.MeV pqBq pq.J pqs^- pq.J/s. In nine hours the body absorbes E_ E_ t pq.J. In a year this is E E_ pq.J. The absorbed energy dose of a pqkg person corresponding to this energy is D fracEm fracpq.Jpqkg pq.Gy. Since isotopeK is a upbeta-emitter both upbeta^+ and upbeta^- occur the q-factor for its radiation is electrons and photons. The equivalent dose hence is H qD pq.Sv. The absorbed dose in a year is pq.upmu Sv and is negligible to pqmSv the normal allowed dose.
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Exercise:
Ase a liter of milk typically has an activity of pqBq due to the upbeta-emitter isotopeK. If a person drinks two glasses pq.l per day estimate the total effective dose in Sievert received in a year. As a crude model ase the milk stays in the stomach for hours and is then released. Ase also that very roughly % of the pq.MeV released per decay is absorbed by the body. Compare your result to the normal allowed dose of pqmSv. Make your estimate for a pqkg adult.
Solution:
Each decay deposits % of its energy pq.MeV in the body i.e. pq.MeV. Since the source's activity is pqBq its deposited energy is E_ pq.MeV pqBq pq.J pqs^- pq.J/s. In nine hours the body absorbes E_ E_ t pq.J. In a year this is E E_ pq.J. The absorbed energy dose of a pqkg person corresponding to this energy is D fracEm fracpq.Jpqkg pq.Gy. Since isotopeK is a upbeta-emitter both upbeta^+ and upbeta^- occur the q-factor for its radiation is electrons and photons. The equivalent dose hence is H qD pq.Sv. The absorbed dose in a year is pq.upmu Sv and is negligible to pqmSv the normal allowed dose.
Ase a liter of milk typically has an activity of pqBq due to the upbeta-emitter isotopeK. If a person drinks two glasses pq.l per day estimate the total effective dose in Sievert received in a year. As a crude model ase the milk stays in the stomach for hours and is then released. Ase also that very roughly % of the pq.MeV released per decay is absorbed by the body. Compare your result to the normal allowed dose of pqmSv. Make your estimate for a pqkg adult.
Solution:
Each decay deposits % of its energy pq.MeV in the body i.e. pq.MeV. Since the source's activity is pqBq its deposited energy is E_ pq.MeV pqBq pq.J pqs^- pq.J/s. In nine hours the body absorbes E_ E_ t pq.J. In a year this is E E_ pq.J. The absorbed energy dose of a pqkg person corresponding to this energy is D fracEm fracpq.Jpqkg pq.Gy. Since isotopeK is a upbeta-emitter both upbeta^+ and upbeta^- occur the q-factor for its radiation is electrons and photons. The equivalent dose hence is H qD pq.Sv. The absorbed dose in a year is pq.upmu Sv and is negligible to pqmSv the normal allowed dose.
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