Recent content by Blue Kangaroo

Ah I made a mistake. I meant to write ∂2E/∂r2

Homework Statement Take ∂2E/∂t2 E(r,t)=E0cos((k(u^·r−ct)+φ) in which u^ is a unit vector. Homework Equations d/dx(cosx)=-sinx The Attempt at a Solution I had calc 3 four years ago and can't for the life of me remember how to differentiate the unit vector. I came up with...

Thank you, I should be able to take it from here.

Homework Statement Suppose that an electric field is given by E(r,t)=E0cos(k·r−ωt+φ), where k⊥E0 and φ is a constant phase. Show that B(r,t)=((k×E)/ω)B(k⋅r-ωt+φ) is consistent with ∇×E=-∂B/∂t Homework Equations ∇×E=-∂B/∂t The Attempt at a Solution I know I have to take the curl of E, but I'm...

Yep, I've already done it. The rest went quickly once I knew what I was doing. Thanks.

Thanks for the help. Now that I take a step back and look at it, I was making it harder than it is.

OK, EQ=1(4πε0)(Q/d2)yhat

Q is the origin of EQ. Would EQ=Qd/α, or p=Qd? I feel like there's something I'm just struggling with in this section that I haven't in previous ones.

Would that expression be the dipole approximation? And both EQ and p would point in -y hat?

So then the E in the equation would be p=αEQ.

The field originates at the point charge Q and at the atom it is E=p/α I believe. Or am I just going in circles?

Well p=qd=αE, so E=qd/α?

According to my book, polarization is the dipole moment per unit volume, in units of C/m2. I believe polarizability is the ease with which something such as an atom is polarized. The polarizability is related to the dipole by p=αE..

Homework Statement A neutral atom with known polarizability α is located at the origin. A point charge Q is situated on the y-axis a large distance d from the atom. (The atom therefore becomes polarized due to the electric field of the point charge.) (a) Find the electric field due to the atom...

OK I solved the problem. I didn't realize I had to upload the file there. So I have that problem fixed. Now my problem is that it's putting the graph the wrong order. I wanted it to be before the conclusion, but for some reason it started the conclusion first and then place the graph the next...