- 写完 Practice Exam
Part 1 mainly covers:
- Coulomb’s Law
- Electric Field
- Gauss’s Law
- Electric Potential
Question: I can deal with this problem, but why exactly?
Solution: There are two ways to solve this problem:
Electric potential is the integral of electric field in respect of the path. Therefore, the rate of change of electric potential over a path is electric field. Consider a function with a value of zero but a flat slope electric potential and electric field can be both zero.
Consider two identical point charges separated by a distance. Since the electric field is going to the opposite direction with the same magnitude right between the center of two charges, the net electric field goes to zero. However, by scalar addition, the point has a non-zero electric potential.
Question: same as above.
Solution: there are two way of solving this problem.
Same as above, but the other way around:
Consider two point charges with opposite signs and the same magnitude of charges. Since the electric field is going to the same direction with the same magnitude right between the center of two charges, the net electric field is non-zero. However, by scalar addition, the net electric potential is zero since they have the same magnitude but opposite signs.
Issue: I got it intuitively, but got the answer wrong because of the sign.
Solution: Read the question carefully and check the sign of charges carefully.
Part 2 covers:
Issue: I got it correctly, but I was confused by option C since I got the way of adding capacitance incorrectly.
Issue: I accidentally put diameter as radius in calculation.
Solution: Do problems in way.
总的来说其实 Kiyoshi 没有犯犯很严重的问题，大概题都能找到解决方案。反而概念性的简单的小问题容易犯错。总的来说还是对于电势和电场方面的基础知识不够牢靠。
To - Be - Done