Recent content by mensa

I'm so confused that no one could give me any answer...Is it because I didn't get the idea through? Please let me know...thx

I'm sorry for not letting you get through,perhaps it's because my poor English.And thank you,Prologue,for the explanation. I totally agree with Prologue's idea.What's more,I guess the book "A Briefer History Of Time" would help a lot,if have a lot of time to read it...In my mind Huygens-Fresnel...

My mother tongue is not English,so I don't know where can you find it. The only thing I know is that Huygens-Fresnel principle is in the diffraction part of light.I guess any optical book would include this.

I've been thinking since u gave this out. I totally agree with the words in #2. But I suggest that this may because the charge can change the field. I've downloaded all the physics courses in OCW but haven't finished then yet. It may help if you tell in which course and at what time.

I guess you need Huygens-Fresnel principle.It's more essential,but I find it also a little hard to get through,expecially the math part

I'm sorry I wasn't here. But I can't catch your point. What I said means,at first n=1,after 12.1eV comes,n=3. n=3 has 3 ways to go as following goto 2,releasing 1.9eV goto 1,releasing 12.1eV but after 3 go to 2,we still have a 2,and this 2 can goto 1,releasing 10.2eV

I've forgot most of atomic physics. But I can show u the process. [a]at first n=1,then comes the electron with 12.1eV,so the energy raises from -13.6 to -1.5,and n=3.Energy always wants to go from the high level to the low level,and at this time we have 3 ways,that is 3->2,2->1,3->1,these are...

in Huygens-Fresnel principle, U(P)=K*∫∫U(Q)*F(θ0，θ0)*exp{ikr}/r*d∑ K=-i/λ; F(θ0，θ0)=0.5(cosθ0+cosθ) is inclination factor; d∑ is a small part of any close surfaces; these are all include in any Beam Optics book I want to demonstrate the spherical wave point source S gives out, all the d∑ in...

to question b) we know that y = f(x) has gradient 3, so y=3x+m, and 4y+3x^2=7 >4(3x+m)+3x^2=7 >3x^2+12x+4m-7=0 at one point only, so the equation above has only one solution, Δ=0 >m=17/4 q c) is easy ^.^