# Recent content by atavistic

1. ### Lagrangian- what potential?

1. Homework Statement There is a joint system of rods and masses.We need to set up Lagrangian. 2. Homework Equations L= T-V , T = Kinetic energy , V = Potential energy 3. The Attempt at a Solution Hey what should we take as the zero of potential. So does the Lagrangian depend...
2. ### Following first order rxn

OK if we are given the following first order rxn: 2N_2O_5 - > 4NO_2 + O_2 The rate constant is k. Now how would we express the rate law for the decomposition of N_2O_5. - d[N_2O_5]/dt = k[N_2O_5] OR - d[N_2O_5]/dt = 2k[N_2O_5] I think it is the latter but I see all books use...
3. ### Conductors and fields

How does grounded-ness preserve the argument?
4. ### Conductors and fields

I had been reading Feynmann lectures , and in it he has shown an argument which proves that E field inside an empty cavity of a conductor is zero.OK. Now he says a similar argument can be used to show that if there is some charge in a cavity of a conductor than the field outside must be zero...
5. ### Another pH

Actually, there are so many equilibria in this solution I cant figure out what will contribute and the assumption I made(given above) seems to give a wrong answer.
6. ### Another pH

1. Homework Statement 50ml of 0.10M Na_3PO_4 + 50ml of 0.10M NaH_2PO_4 For H_2CO_3: Ka_1 = 7.5 * 10^{ - 3} Ka_2 = 6.2 * 10^{ - 8} Ka_3 = 1.0 * 10^{ - 12} 2. Homework Equations 3. The Attempt at a Solution Since K_h of Na_3PO_4 > > Ka_2 , I considered only hydrolysis of...
7. ### Find pH of 0.1 MNaHCO3

1. Homework Statement Find pH of 0.1M NaHCO_3 Ka_1 (H_2CO_3) = 4.3 * 10^{ - 7} , Ka_2 (H_2CO_3) = 5.61 * 10^{ - 11} 2. Homework Equations pH = \frac {1}{2}(14 + pKa_1 + logC) 3. The Attempt at a Solution Now K_h = \frac {Kw}{Ka_1} = 2.3 * 10^{ - 8} > > Ka2 So I neglect dissociation...
8. ### Modern Physics

Ok then D right? Thnx for replies.
9. ### Modern Physics

Well what if the experiment is done only once.? If its done many times, answer is probably "d".
10. ### Modern Physics

1. Homework Statement A single electron with de Broglie wavelength \lambda passes through a slit of width d = 2\lambda. The electron can then strike a flourescent screen. What will be observed on the screen? a) A diffraction pattern b) A single flash has if the electron had moved in a...
11. ### Center of gravity vs center of mass

Is it different from the center of mass? My book says yes but doesnt answer the question.
12. ### Thick Double Slit

To notice patterns you need very thin slits, if you have thick slits you wont be able to notice any change since construction destruction all occur so close together.
13. ### Emfs, work and heat

When we say heat released in a circuit is i^2 RT , who/what is the cause of this energy loss; is it the battery mechanism? Since work done on charge in the circuit by E field is zero, the only other force seems to be the battery mechanism, right? But in text books there is so much implication...
14. ### Standing wave energy

Well can you tell me what I did is right or not and the thing about PE.
15. ### Average value of AC over a complete cycle is always zero

Re: Ac Is this the right place to post this?