Leistungszahl eines Gefrierschrankes
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 \(m\) / Temperatur \(T\) / Arbeit \(W\) / Energie \(E\) / Leistung \(P\) / Wärme \(Q\) / spezifische latente Wärme \(L\) / Wärmekapazität \(c\) / Leistungszahl \(\epsilon\) /
The following formulas must be used to solve the exercise:
\(Q = c \cdot m \cdot \Delta\vartheta \quad \) \(Q = m \cdot L_{\scriptscriptstyle\rm f} \quad \) \(P = \dfrac{E}{t} = \dfrac{W}{t} \quad \) \(\epsilon = \frac{Q_L}{W} \quad \)
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Exercise:
Stellt man .kg Wasser bei anfänglich wtO in einen Gefrierschrank so wird es innerhalb von tO zu Eis bei etO gefroren. Der Gefrierschrank zieht dazu PO Leistung aus dem elektrischen Netz. Wie gross ist seine Leistungszahl? Die spezifische Wärmekapazität von Wasser beträgt jouleperkilogramperkelvin die von Eis jouleperkilogramperkelvin und die spezifische Schmelzwärme beträgt .ejouleperkilogram.
Solution:
Insgesamt muss dem Innern des Gefrierschrankes folge Wärme entzogen werden damit das Wasser zu Eis der angegebenen Temperatur gefriert: Q_L c_texttiny WmDeltatheta_texttiny W + mL_f + c_texttiny EmDeltatheta_texttiny E jouleperkilogramperkelvin .kg K + .kg .ejouleperkilogram + jouleperkilogramperkelvin .kg K .eJ Der Gefrierschrank bezieht dafür währ zwei Stunden aus dem elektrischen Netz folge elektrische Energie: W Pt W s .eJ Er hat somit folge Leistungszahl: epsilon fracQ_LW fracc_texttiny W mDeltatheta_texttiny W + mL_f + c_texttiny EmDeltatheta_texttiny EPt fracmc_texttiny W Deltatheta_texttiny W + L_f + c_texttiny EDeltatheta_texttiny EPt frac.eJ.eJ .
Stellt man .kg Wasser bei anfänglich wtO in einen Gefrierschrank so wird es innerhalb von tO zu Eis bei etO gefroren. Der Gefrierschrank zieht dazu PO Leistung aus dem elektrischen Netz. Wie gross ist seine Leistungszahl? Die spezifische Wärmekapazität von Wasser beträgt jouleperkilogramperkelvin die von Eis jouleperkilogramperkelvin und die spezifische Schmelzwärme beträgt .ejouleperkilogram.
Solution:
Insgesamt muss dem Innern des Gefrierschrankes folge Wärme entzogen werden damit das Wasser zu Eis der angegebenen Temperatur gefriert: Q_L c_texttiny WmDeltatheta_texttiny W + mL_f + c_texttiny EmDeltatheta_texttiny E jouleperkilogramperkelvin .kg K + .kg .ejouleperkilogram + jouleperkilogramperkelvin .kg K .eJ Der Gefrierschrank bezieht dafür währ zwei Stunden aus dem elektrischen Netz folge elektrische Energie: W Pt W s .eJ Er hat somit folge Leistungszahl: epsilon fracQ_LW fracc_texttiny W mDeltatheta_texttiny W + mL_f + c_texttiny EmDeltatheta_texttiny EPt fracmc_texttiny W Deltatheta_texttiny W + L_f + c_texttiny EDeltatheta_texttiny EPt frac.eJ.eJ .
Meta Information
Exercise:
Stellt man .kg Wasser bei anfänglich wtO in einen Gefrierschrank so wird es innerhalb von tO zu Eis bei etO gefroren. Der Gefrierschrank zieht dazu PO Leistung aus dem elektrischen Netz. Wie gross ist seine Leistungszahl? Die spezifische Wärmekapazität von Wasser beträgt jouleperkilogramperkelvin die von Eis jouleperkilogramperkelvin und die spezifische Schmelzwärme beträgt .ejouleperkilogram.
Solution:
Insgesamt muss dem Innern des Gefrierschrankes folge Wärme entzogen werden damit das Wasser zu Eis der angegebenen Temperatur gefriert: Q_L c_texttiny WmDeltatheta_texttiny W + mL_f + c_texttiny EmDeltatheta_texttiny E jouleperkilogramperkelvin .kg K + .kg .ejouleperkilogram + jouleperkilogramperkelvin .kg K .eJ Der Gefrierschrank bezieht dafür währ zwei Stunden aus dem elektrischen Netz folge elektrische Energie: W Pt W s .eJ Er hat somit folge Leistungszahl: epsilon fracQ_LW fracc_texttiny W mDeltatheta_texttiny W + mL_f + c_texttiny EmDeltatheta_texttiny EPt fracmc_texttiny W Deltatheta_texttiny W + L_f + c_texttiny EDeltatheta_texttiny EPt frac.eJ.eJ .
Stellt man .kg Wasser bei anfänglich wtO in einen Gefrierschrank so wird es innerhalb von tO zu Eis bei etO gefroren. Der Gefrierschrank zieht dazu PO Leistung aus dem elektrischen Netz. Wie gross ist seine Leistungszahl? Die spezifische Wärmekapazität von Wasser beträgt jouleperkilogramperkelvin die von Eis jouleperkilogramperkelvin und die spezifische Schmelzwärme beträgt .ejouleperkilogram.
Solution:
Insgesamt muss dem Innern des Gefrierschrankes folge Wärme entzogen werden damit das Wasser zu Eis der angegebenen Temperatur gefriert: Q_L c_texttiny WmDeltatheta_texttiny W + mL_f + c_texttiny EmDeltatheta_texttiny E jouleperkilogramperkelvin .kg K + .kg .ejouleperkilogram + jouleperkilogramperkelvin .kg K .eJ Der Gefrierschrank bezieht dafür währ zwei Stunden aus dem elektrischen Netz folge elektrische Energie: W Pt W s .eJ Er hat somit folge Leistungszahl: epsilon fracQ_LW fracc_texttiny W mDeltatheta_texttiny W + mL_f + c_texttiny EmDeltatheta_texttiny EPt fracmc_texttiny W Deltatheta_texttiny W + L_f + c_texttiny EDeltatheta_texttiny EPt frac.eJ.eJ .
Contained in these collections:
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Leistung eines Kühlschrankes by TeXercises
Asked Quantity:
Leistungszahl \(\epsilon\)
in
Leistungszahl \(\rm 1\)
Physical Quantity
Unit