Lens
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
\(\LaTeX\)
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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:
A lens with diameter daO is used to concentrate the sunlight onto a bright spot with a diameter dbO. Calculate the factor by which the electric field amplitude at the bright spot is greater than immediately before the lens.
Solution:
Asing that the power of the light entering the lens is equal to the power at the bright spot i.e. that there is no absorption in the lens the ratio of the ensities at the bright spot and before the lens is fracI__L fracA_LA_S fracd_L^d_S^ leftfracd_Ld_Sright^ labeleq_area We also know that the ensity is proportional to the square of the electric field: fracI__L leftfracE_SE_Lright^ labeleq_field Combining refeq_area and refeq_field yields leftfracE_SE_Lright^ leftfracd_Ld_Sright^ Longrightarrow fracE_SE_L ratioF fracdadb resultratioP
A lens with diameter daO is used to concentrate the sunlight onto a bright spot with a diameter dbO. Calculate the factor by which the electric field amplitude at the bright spot is greater than immediately before the lens.
Solution:
Asing that the power of the light entering the lens is equal to the power at the bright spot i.e. that there is no absorption in the lens the ratio of the ensities at the bright spot and before the lens is fracI__L fracA_LA_S fracd_L^d_S^ leftfracd_Ld_Sright^ labeleq_area We also know that the ensity is proportional to the square of the electric field: fracI__L leftfracE_SE_Lright^ labeleq_field Combining refeq_area and refeq_field yields leftfracE_SE_Lright^ leftfracd_Ld_Sright^ Longrightarrow fracE_SE_L ratioF fracdadb resultratioP
Meta Information
Exercise:
A lens with diameter daO is used to concentrate the sunlight onto a bright spot with a diameter dbO. Calculate the factor by which the electric field amplitude at the bright spot is greater than immediately before the lens.
Solution:
Asing that the power of the light entering the lens is equal to the power at the bright spot i.e. that there is no absorption in the lens the ratio of the ensities at the bright spot and before the lens is fracI__L fracA_LA_S fracd_L^d_S^ leftfracd_Ld_Sright^ labeleq_area We also know that the ensity is proportional to the square of the electric field: fracI__L leftfracE_SE_Lright^ labeleq_field Combining refeq_area and refeq_field yields leftfracE_SE_Lright^ leftfracd_Ld_Sright^ Longrightarrow fracE_SE_L ratioF fracdadb resultratioP
A lens with diameter daO is used to concentrate the sunlight onto a bright spot with a diameter dbO. Calculate the factor by which the electric field amplitude at the bright spot is greater than immediately before the lens.
Solution:
Asing that the power of the light entering the lens is equal to the power at the bright spot i.e. that there is no absorption in the lens the ratio of the ensities at the bright spot and before the lens is fracI__L fracA_LA_S fracd_L^d_S^ leftfracd_Ld_Sright^ labeleq_area We also know that the ensity is proportional to the square of the electric field: fracI__L leftfracE_SE_Lright^ labeleq_field Combining refeq_area and refeq_field yields leftfracE_SE_Lright^ leftfracd_Ld_Sright^ Longrightarrow fracE_SE_L ratioF fracdadb resultratioP
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