# Search results

thank you!
2. ### The Magnitude of the Poynting Vector

That makes sense, I guess the thing that is throwing me off is the "time-average". Intensity = time average of S I = <S> I= (1/2)*c*epsilon not*Emax^2 Can I say then that magnitude of I = magnitude of S or would I have to say magnitude of I = (1/2)*c*epsilon not*Emax^2 = (1/2) * S
3. ### The Magnitude of the Poynting Vector

General question: Is the magnitude of the poynting vector equal to the intensity of an electromagnetic wave? I know that I= average S which makes me think that I cannot simply assume that that their magnitudes are equal!?
4. ### Resonance curve

i don't! :( All I have is the natural frequency in rad/sec.
5. ### Resonance curve

Homework Statement if i know the natural frequency of a system, how can I generate a resonance curve for the system in terms of frequency vs amplitude. The Attempt at a Solution I know it will have one peak, like a bell curve and the max will be the natural frequency, but i don't...
6. ### Random Number Histogram

[b]1. The problem statement If i generate a list of 300 random numbers in excel, each number between 1-50 for example, and i plot the frequency that each number comes in a histogram, how can i tell, looking at the histogram, if the numbers are really random? is there a certain distribution...
7. ### X-ray diffraction

This is not really a homework question but a more general plea for an explenation from someone! :) In x-ray diffraction, you get a graph with different peaks that are particular to the composition of your sample. But, why are some peaks are of higher intesities then others? What is it about...
8. ### Impurity doping

What is impurity doping? Can somebody please explain it?
9. ### Simple Junction Rule question

Thanks again! :) :) :)
10. ### Simple Junction Rule question

Thank you so much! oh ok, so it would just be I(3)+I(2)=I(1) right?
11. ### Simple Junction Rule question

Homework Statement I need to find the current equation for the junction in node a in the following circuit: http://i749.photobucket.com/albums/xx137/abcdmichelle/gjgjhg.jpg Homework Equations Current in = Current out so I(in)=I(out) The Attempt at a Solution The arrows in the...
12. ### Circuit: Potential Difference

Homework Statement For the circuit in the figure below, V = 3.56 V and R = 2.04 Ω. Find the potential difference between points a and b. This is the link to the figure: http://i749.photobucket.com/albums/xx137/abcdmichelle/physics/26-62alt1.gif Homework Equations V=IR The Attempt...
13. ### Parallel Capacitor

Thank you so so so much! What great help!
14. ### Parallel Capacitor

Thank you Hellabyte! :) If I find V, then I know how to find E. So, V=Work/charge V=(0.5mv^2)/q thus V=(0.5MS^2)/Q Is this correct? I think it is, and from here I know how to do all the problem...assuming it is correct!?
15. ### Parallel Capacitor

Homework Statement A parallel plate capacitor has two conducting plates separated by a vacuum. The distance is D and the area of each plate is A. An alpha particle with mass M and charge Q is placed on the positively-charged plate, between the plates. It shoots through a small hole in the...
16. ### Gauss' Law: Cylindrical sheath

Thank you very very much Doc Al! This makes so much sense!
17. ### Gauss' Law: Cylindrical sheath

Thank you Doc Al! So for r=17, if R is the outer radius of the sheath, then Q=rho(length)piR^2, so E=(rho(length)piR^2)/(2pi(length)r(epsilon_o), thus E=(rhoR^2)/(2r(epsilon_o)) is that correct, where i would use r=17 and R=15?? I still don't know how I would figure out E for r=12, the...
18. ### Gauss' Law: Cylindrical sheath

Homework Statement A non-conducting, infinitely long, cylindrical sheath has inner radius r=10 m, outer radius r=15 m and a uniform charge density of 9 nC/m^3 spread throughout the sheath. Magnitude of electric field at r=5, r=12, r=17? Homework Equations Q=rho(Volume) and phi=EA...