Filament Temperature
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
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Exercise:
The temperature of the tungsten filament in a lightbulb can be estimated from the lightbulb’s resistance at room temperature TrO and in operation. At room temperature the resistance of a VO/PO light bulb is measured to be RrO. Asing a linear relation between resistance and temperature calculate the filament temperature when the light bulb is on. Is the real value lower or higher?
Solution:
When the light bulb is on its resistance is given by R fracDelta VI fracDelta VfracPDelta V fracDelta V^P It follows for the temperature coefficient alpha_ fracDelta RR_ Delta T fracR-R_R_ Delta T fracfracDelta V^P-R_R_ Delta T fracDelta V^ - P R_P R_ Delta T Solving for the temperature increase yields Delta T fracDelta V^-R_PP R_ alpha_ The filament temperatre in operation is then T T_ + Delta T TF Tr + fracV^-P times RrP times Rr times al T approx resultTS The real value is lower because the resistivity increases more than the linear tr i.e. it reaches the operational temperature at a lower temperature than predicted by the linear model.
The temperature of the tungsten filament in a lightbulb can be estimated from the lightbulb’s resistance at room temperature TrO and in operation. At room temperature the resistance of a VO/PO light bulb is measured to be RrO. Asing a linear relation between resistance and temperature calculate the filament temperature when the light bulb is on. Is the real value lower or higher?
Solution:
When the light bulb is on its resistance is given by R fracDelta VI fracDelta VfracPDelta V fracDelta V^P It follows for the temperature coefficient alpha_ fracDelta RR_ Delta T fracR-R_R_ Delta T fracfracDelta V^P-R_R_ Delta T fracDelta V^ - P R_P R_ Delta T Solving for the temperature increase yields Delta T fracDelta V^-R_PP R_ alpha_ The filament temperatre in operation is then T T_ + Delta T TF Tr + fracV^-P times RrP times Rr times al T approx resultTS The real value is lower because the resistivity increases more than the linear tr i.e. it reaches the operational temperature at a lower temperature than predicted by the linear model.
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Exercise:
The temperature of the tungsten filament in a lightbulb can be estimated from the lightbulb’s resistance at room temperature TrO and in operation. At room temperature the resistance of a VO/PO light bulb is measured to be RrO. Asing a linear relation between resistance and temperature calculate the filament temperature when the light bulb is on. Is the real value lower or higher?
Solution:
When the light bulb is on its resistance is given by R fracDelta VI fracDelta VfracPDelta V fracDelta V^P It follows for the temperature coefficient alpha_ fracDelta RR_ Delta T fracR-R_R_ Delta T fracfracDelta V^P-R_R_ Delta T fracDelta V^ - P R_P R_ Delta T Solving for the temperature increase yields Delta T fracDelta V^-R_PP R_ alpha_ The filament temperatre in operation is then T T_ + Delta T TF Tr + fracV^-P times RrP times Rr times al T approx resultTS The real value is lower because the resistivity increases more than the linear tr i.e. it reaches the operational temperature at a lower temperature than predicted by the linear model.
The temperature of the tungsten filament in a lightbulb can be estimated from the lightbulb’s resistance at room temperature TrO and in operation. At room temperature the resistance of a VO/PO light bulb is measured to be RrO. Asing a linear relation between resistance and temperature calculate the filament temperature when the light bulb is on. Is the real value lower or higher?
Solution:
When the light bulb is on its resistance is given by R fracDelta VI fracDelta VfracPDelta V fracDelta V^P It follows for the temperature coefficient alpha_ fracDelta RR_ Delta T fracR-R_R_ Delta T fracfracDelta V^P-R_R_ Delta T fracDelta V^ - P R_P R_ Delta T Solving for the temperature increase yields Delta T fracDelta V^-R_PP R_ alpha_ The filament temperatre in operation is then T T_ + Delta T TF Tr + fracV^-P times RrP times Rr times al T approx resultTS The real value is lower because the resistivity increases more than the linear tr i.e. it reaches the operational temperature at a lower temperature than predicted by the linear model.
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