Introduction
From this material students can learn about the electric field, its source and charge.
The students are supposed to watch a video material and then answer a series of questions based on the mentioned topic and calculate a task.
After the answers are filled in, they should check their answers and estimate their knowledge on this subject.
Task
The objectives are to learn about the electric field from a video material and then answer a series of questions based on this material and try to calculate a single task.
The questions require a ''Yes'' or a ''No'' answer. If the question is answered with a ''No'', then, please, correct the question so the answer would be correct.
Process
The students must watch the video material and afterwards answer these questions and calculate the given task.
The questions:
1) Are electrical fields created by electrical charges?
2) If there are 2 negative charges, are they going to gravitate?
3) Is the definition of the electric field ''E equals F divided by q'' ?
4) Are the SI units coulombs per newton?
5) Is Coulomb's law used to describe the force interacting between static electrically charged particles?
6) Do electromagneticwaves have both electric field and magnetic field?
7) Electric fields are static and dynamic.
8) Do electric field have a clear direction and a specific intensity?
9) If we get further away from the charge, does the strenght of the electric field increases?
10) Does the unit k equals 9*10^9 (N*m^2)/C^2 ?
The task:
A metal orb has a negative charge of 1,6*10^-7 C. How many electrons flow away from the orb by discharging it?
Evaluation
By answering each of these questions correctly the students can gather 20 points, meaning 2 points for each question. If the negative answers do not have a correction, the student recieves only 1 point.
1) Yes.
2) No, if there were a negative and a positive charge, then they would gravitate towards one another.
3) Yes.
4) No, it's newtons per coulomb.
5) Yes.
6) Yes.
7) No, they are either static or dynamic.
8) Yes.
9) No, the further we got from the charge, the weaker the electrical field.
10) Yes.
By finishing this task correctly, the students can earn 5 points. One point each for finding the necessary unit, writting the formula, modifying the formula to the exact situation, calculating the answer and writting it down.
The solution to the task:
A metal orb has a negative charge of 1,6*10^-7 C. How many electrons flow away from the orb by discharging it?
q= 1,6*10^-7 C (given from the instructions)
e= 1,6*10^-19 C (fundamental elementary charge constant)
We need to find N.
The formula is q=N*e , but we need to calculate N, so let's modify the formula.
N= q/e
N= 1,6*10^-7 / 1,6*10^-19 = 1*10^12
The aswer is : By discharging the orb 1*10^12 electrons are flowing away.
Conclusion
The scores of the tests:
22-25 Excellent. Have understood the subject and the tasks very well.
21-18 Well done. Done the job with slight mishaps, but overall understood the subject.
17-11 Average. Have passed the tasks, the subject is partly not understood.
10-5 Below average. Have done a poor job and have not fully understood the subject.
4-0 Failing. Have not passed the tasks and did not understood the subject at all.
For those who scored 10 points and less are recommended to watch the video material again and try to understand their mistakes and to correct them.