Horizontal wire -- current
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:
elektrische Stromstärke \(I\) / Magnetische Flussdichte \(B\) / Winkel \(\theta\) /
The following formulas must be used to solve the exercise:
\(\cos\alpha = \dfrac{b}{c} \quad \) \(B = \dfrac{\mu_0 I}{2\pi r} \quad \) \(a^2+b^2=c^2 \quad \)
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Exercise:
A very long horizontal cable carries an unknown current due to north. Calculate this current knowing that the resulting magnetic field pqcm due to west of the wire is pq.T poing upward at unknown angle above the horizontal and the Earth's field there pos north but downward degree below the horizontal and has magnitude pq.T.
Solution:
The horizontal component of Earth's magnetic field is: B_h B_EarthIndex cosgrad pq.T Since the magnetic field of the horizontal wire is vertical the horizontal component of the resulting magnetic field is also B_hpq.T. With this in mind we can calculate the angle of the resulting magnetic field: alpha arccosleftfrac..right .grad The vertical component of Earth's field and the resulting field are B_ B_EarthIndex singrad pq.T B_ B_textscriptsize res sin.grad pq.T Therefore the magnetic field from the wire is pq.T. The current necessary is therewith I fracpi r Bmu_ pq.A.
A very long horizontal cable carries an unknown current due to north. Calculate this current knowing that the resulting magnetic field pqcm due to west of the wire is pq.T poing upward at unknown angle above the horizontal and the Earth's field there pos north but downward degree below the horizontal and has magnitude pq.T.
Solution:
The horizontal component of Earth's magnetic field is: B_h B_EarthIndex cosgrad pq.T Since the magnetic field of the horizontal wire is vertical the horizontal component of the resulting magnetic field is also B_hpq.T. With this in mind we can calculate the angle of the resulting magnetic field: alpha arccosleftfrac..right .grad The vertical component of Earth's field and the resulting field are B_ B_EarthIndex singrad pq.T B_ B_textscriptsize res sin.grad pq.T Therefore the magnetic field from the wire is pq.T. The current necessary is therewith I fracpi r Bmu_ pq.A.
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Exercise:
A very long horizontal cable carries an unknown current due to north. Calculate this current knowing that the resulting magnetic field pqcm due to west of the wire is pq.T poing upward at unknown angle above the horizontal and the Earth's field there pos north but downward degree below the horizontal and has magnitude pq.T.
Solution:
The horizontal component of Earth's magnetic field is: B_h B_EarthIndex cosgrad pq.T Since the magnetic field of the horizontal wire is vertical the horizontal component of the resulting magnetic field is also B_hpq.T. With this in mind we can calculate the angle of the resulting magnetic field: alpha arccosleftfrac..right .grad The vertical component of Earth's field and the resulting field are B_ B_EarthIndex singrad pq.T B_ B_textscriptsize res sin.grad pq.T Therefore the magnetic field from the wire is pq.T. The current necessary is therewith I fracpi r Bmu_ pq.A.
A very long horizontal cable carries an unknown current due to north. Calculate this current knowing that the resulting magnetic field pqcm due to west of the wire is pq.T poing upward at unknown angle above the horizontal and the Earth's field there pos north but downward degree below the horizontal and has magnitude pq.T.
Solution:
The horizontal component of Earth's magnetic field is: B_h B_EarthIndex cosgrad pq.T Since the magnetic field of the horizontal wire is vertical the horizontal component of the resulting magnetic field is also B_hpq.T. With this in mind we can calculate the angle of the resulting magnetic field: alpha arccosleftfrac..right .grad The vertical component of Earth's field and the resulting field are B_ B_EarthIndex singrad pq.T B_ B_textscriptsize res sin.grad pq.T Therefore the magnetic field from the wire is pq.T. The current necessary is therewith I fracpi r Bmu_ pq.A.
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Horizontal wire by TeXercises