Help with E&M Questions: Answers, Explanations & Reviews

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In summary, E&M, or Electromagnetism, is a branch of physics that deals with the study of electric and magnetic fields and their interactions with charged particles. "Help with E&M Questions" covers common topics such as electric fields, magnetic fields, electromagnetism, electromagnetic waves, and circuit analysis. It provides answers, explanations, and reviews to aid in understanding E&M concepts. The answers are written by experts and have been reviewed for accuracy, making them reliable. Additionally, "Help with E&M Questions" can be used as a study tool for exam preparation by testing understanding of key concepts and identifying areas for further review.
  • #1
compscier
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Help with E&M?
1) http://tinyimage.net/images/25790944428468568236.png [Broken]
I don't even... The answer is B.. What should I review??

2)http://tinyimage.net/images/81684598844478119651.png [Broken]
Why can't I use the formula V^2/R for this one?? answer C btw ( I did get it right, but just because I didn't see the answer choice I needed had I used V^2/R...)

3)http://tinyimage.net/images/14929814429358178541.png [Broken]
How do I approach questions like 52? The answer is E... (I get 51 though)

4)http://tinyimage.net/images/89661487184785817963.png [Broken]
Umm... I don't remember learning this.. What is this an application of?

5)http://tinyimage.net/images/05849919813601766271.png [Broken]
57:B -> Why is R2 ignored? I put A originally...
58:A -> I thought there is no current after a significant amount of time b/c capacitor takes up all the charge? no?
 
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  • #2
That's a lot of stuff for one thread !
 
  • #3
they are sort of simple questions... I guess I'll make separate threads for each then...
 
  • #4
compscier said:
Help with E&M?
1) http://tinyimage.net/images/25790944428468568236.png [Broken]
I don't even... The answer is B.. What should I review??
Maxwell's correction to Ampere's Law.
2)http://tinyimage.net/images/81684598844478119651.png [Broken]
Why can't I use the formula V^2/R for this one?? answer C btw ( I did get it right, but just because I didn't see the answer choice I needed had I used V^2/R...)
Read the question. Its wording basically tells you to use I2R, where R is written in terms of resistivity, length & cross-section.
3)http://tinyimage.net/images/14929814429358178541.png [Broken]
How do I approach questions like 52? The answer is E... (I get 51 though)
Do you know how to calculate electric potential?
4)http://tinyimage.net/images/89661487184785817963.png [Broken]
Umm... I don't remember learning this.. What is this an application of?
Review your notes. How is electric potential related to potential energy?
5)http://tinyimage.net/images/05849919813601766271.png [Broken]
57:B -> Why is R2 ignored? I put A originally...
Initially the potential across the capacitor is zero -- like a short circuit.
58:A -> I thought there is no current after a significant amount of time b/c capacitor takes up all the charge? no?
Eventually, the capacitor will not charge anymore, so there is no current through it, but there is still current through R2.
 
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  • #5


1) For question 1, the answer is B because the electric field lines are perpendicular to the surface of the conductor, which is a property of a conductor in electrostatic equilibrium. To review, you can go over the concept of electric fields and their behavior around conductors in electrostatic equilibrium.

2) In question 2, the formula V^2/R is only applicable for circuits with resistors. In this circuit, there is a capacitor, which behaves differently than a resistor and requires a different formula (Q=CV). To avoid confusion, make sure to carefully read the question and identify all components in the circuit before applying any formulas.

3) For question 3, the answer is E because the electric field lines are pointing towards the negative charge, which is opposite to the direction of the electric field lines from a positive charge. To approach this type of question, it is helpful to draw a diagram and visualize the direction of the electric field lines. Remember that electric field lines always point away from positive charges and towards negative charges.

4) Question 4 is an application of Gauss's Law, which states that the electric flux through a closed surface is equal to the charge enclosed by that surface divided by the permittivity of free space. In this case, the electric flux is equal to the charge enclosed by the Gaussian surface, which is the sphere, multiplied by the permittivity of free space. Reviewing this concept will help you understand this type of problem.

5) For question 5, the answer to 57 is B because the electric field lines are perpendicular to the surface of the conductor, which is a property of a conductor in electrostatic equilibrium. R2 is ignored because it does not contribute to the electric field in this configuration. For question 58, the answer is A because the capacitor does not reach full charge instantaneously and there will still be a current flowing initially. As time goes on, the current will decrease until it reaches zero. Reviewing the behavior of capacitors in circuits will help you understand these questions.
 

1. What is E&M (Electromagnetism)?

E&M, or Electromagnetism, is a branch of physics that deals with the study of electric and magnetic fields and their interactions with charged particles. It also includes the study of electromagnetic radiation, such as light and radio waves.

2. What are some common topics covered in "Help with E&M Questions"?

Some common topics covered in "Help with E&M Questions" include electric fields, magnetic fields, electromagnetism, electromagnetic waves, and circuit analysis.

3. How can "Help with E&M Questions" aid in my understanding of E&M concepts?

"Help with E&M Questions" provides answers, explanations, and reviews of common E&M questions, which can help clarify difficult concepts and reinforce your understanding of the subject.

4. Are the answers provided in "Help with E&M Questions" reliable?

Yes, the answers provided in "Help with E&M Questions" are written by experts in the field of E&M and have been reviewed for accuracy. However, it is always recommended to double-check with other reliable sources.

5. How can I use "Help with E&M Questions" to prepare for exams?

"Help with E&M Questions" can serve as a valuable study tool for exam preparation. By reviewing common questions and their answers, you can test your understanding of key concepts and identify any areas that may need further review.

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