# Search results

1. ### Early earth - silicates

How did the silicates form during the period in which a gas of silica coalesced into a ball of molten silicon? I thought silicate typically only forms in basic aqueous solutions, which clearly did not exist at this period.
2. ### Electron spin entanglements - time-energy uncertainty

I've been watching Susskind's lectures on quantum mechanics and he mentions that the time taken for two electrons to entangle their spin is a function of their distance, which in itself determines the energy that is released when two electrons fall into a singlet state. Does anyone here know how...
3. ### Magnetic pressure and bar magnets

So it has been puzzling me that the repulsion and attraction between two bar magnetics can be considered as a consequence of magnetic field energy density - that is magnetic pressure. I realise 1/2B^2/mu_0 is the pressure and that times the area gives the force. But conceptually I don't...
4. ### Chadwick's experiment and proton velocity

How did he measue the proton velocity in the polonium-beryllium experiment? The only source with some description describes his using current as a means to do so - but sure that would require knowledge of the number of protons in order to ascertain the drift velocity?
5. ### Statistics - related pdfs

Homework Statement I am given the lens maker's equation: 1/u + 1/v = 1/f Then told that U and V are random variables based on this equation. U is uniformly distributed between 2f and 3f. The question is to prove the pdf of V is f/(v-f)^2 and find the cdf for V. Also - find the...
6. ### Complex cube root of 1

Homework Statement If w is a complex cube root of 1, prove that x + wy + w^2z is a factor of x^3+ y^3 + z^3 - 3xyz, and hence factorise the equation completely. Homework Equations Complex cube root of 1 = -1/2 +/- 3^1/2/2 i The Attempt at a Solution Erm, I feel way over my head...