Recent content by v_pino

Homework Statement Given the following information, derive and expression to calculate the capillary depression of mercury in a glass tube given that: Contact angle = 140 degrees Surface tension 'Gamma' = 0.476 Nm^-1 Tube diameter = 1.0mm Density of mercury 'rho' = 13.58x10^3 kgm^-3...

Doesn't the mass attenuation coefficient take into account of a 3D source? Should I use it in the equation I=I_0 exp(-mu * x) ? Can I say that the final intensity I for case (A) is 1000? Then use this to find the initial intensity in case (A). Then assuming the initial intensity is same in (A)...

Homework Statement I've attached the problem sheet and my attempt at the problem. I've completed all the parts except for the last part, where I have to calculate the count rate of the radioactive source. The answers should be 6000 counts for 185MeV and 4650 counts for 1MeV. I'm not sure...

Does a collision that happens in water have a stronger impact than a collision on land?

Homework Statement A beam of neutrons traveling in the x direction initially has all its spins up along the z direction. The neutrons pass through a region in which there is a uniform 1 tesla magnetic field in the y direction. What is the minimum time t the neutrons need to remain in the...

Homework Statement How do I obtain [H,P_x]? P_x is the polarization operator. Homework Equations H=-\frac{\hbar^2}{2m}\frac{\partial^2 }{\partial x^2}+V(x) P_x=2Re[c_+^*c_-] The Attempt at a Solution I know how to commute H and x. But somehow can't think of a way to...

Homework Statement I'm part way through a problem and got the answer P_x=c_+^* c_-+c_-^*c_+ . But the answer should be 2Re(c+^*c_-) . Are the two equivalent? Homework Equations c+c^*=2Re(c)

Also, I forgot to say that I got this : V(0)/2=\frac{3 \hbar^2 a^2}{8m}

Homework Statement For the (unnormalized) wave function ψ(x) = sech(ax), find the potential energy V (x), and show that the ground-state energy E1 is V(0)/2. The energies are in units of (hbar)^2a^2/2m. Homework Equations - \frac{\hbar}{2m}\frac{d^2 \psi}{dx^2}+V(x) \psi)=E \psi...

got it - thanks

Is this right? = (\frac {n^3}{(n+1)^2}-n)\frac{E_1 \hbar^2}{mk^2e^4} The non bracket is now very big: 1.045*10^40. I think the bracket tends to -2.

Is v_n=\frac{Zke^2}{n \hbar}=\frac{Z\alpha c}{n} ?

I now have the ratio = (\frac {n^3}{(n+1)^2}-n)\frac{E_1 \hbar^2}{mk^2e^2} But when I evaluate the non-bracket side, I get 1.28*10^-38. Multiplying this to the bracket doesn't give me a value that tends to 1.

Now I have \frac{\nu_{Bohr}}{\nu_{Orbit}}=(\frac{n}{(n+1)^2}-1 )\frac{Z^2E_1}{h} \frac{2 \pi r}{v} using r_n=\frac{n^2}{Z}a_0 . But even so, this only tells me that the brackets value is getting very small at large n.

Homework Statement In Bohr’s hydrogen atom, the frequency of radiation for transitions between adjacent orbits is νBohr = (En+1−En)/h. Classically, a charged particle moving in a circular orbit radiates at the frequency of the motion, νorbit = v/2πr. Find the ratio νBohr/νorbit for the...