Recent content by ussrasu

The formula is 1/lamba = R (1/2^2 - 1/n^2) sorry if that doesn't make sense But i will put in the number 2 in n for one wavelength and infinity for the other wavelength - and then subtract the 2 answers to get the wavelength range? Is this along the right lines?

In the textbook in a previous example - it says that the C-14 activity in a living tree is 255 Bq - that is where i got that value from but i wasnt sure if i could use that value in this question - ie is it always 255 Bq in living trees?!? The half-life is in s^-1 - therefore the answer...

Thanks for that

Yeh but what i don't understand is how many different energy levels there are for each of the series? Like does it go on forever or does it stop at a certain number? Ie they start at n = 2 or n = 3, but where do they stop? Do they go up to infinity? Is it as simple as plugging the number in for...

Q: What are the widths of the wavelength intervals over which (a) the Lyman series and (b) the Balmer series extend? (Each width begins at the longest wavelength and ends at the series limit.) (c) What are the widths of the corresponding frequency intervals? Express the frequency intervals in...

Q: A 50-g chunk of charcoal is found in the buried remains of an ancient city destroyed by invaders. The carbon-14 activity of the sample is 200 decays/min. Roughly when was the city destroyed? A: I used R = Ro*e^(-lambda*t) and t1/2 = ln2/lambda t1/2 = 3.834*10^-12 s-1 and 200...

Q: What is the minimum amount of energy necessary to remove a proton from the nucleus of a 42-Ca atom, thereby converting it into a 41-K atom? The former has a mass of 41.958618 u, the latter 40.961825 u, and the hydrogen atom has a mass of 1.007825 u. My answer: 42-Ca --> 41-K + 1-H...

This is what my demonstrator told me to use?

Can some please review this question and tell me if the working looks correct? Please advise of any mistakes i may have made. Thanks Q: UV radiation (wavelength = 250 nm) falls on a metal target, and electrons are liberated. If the maximum kinetic energy of these electrons is 1.00*10^-19 J...

Q: Approximate the minimum kinetic energy of an electron confined to a region the size of an atom (0.10 nm) How would one go about solving this? What equations/principles are involved and how do we use them? Seems like a simple question but i have no idea where to start? :confused...

I don't know how to do it - with the small amount of info given? Can someone show me how to work it out please? Thanks! :smile:

What happens in each of the situations though? i.e in parts a) b) and c) - what is different in each of them? And how do you explain these observations in terms of Gauss' Law and Flux? Thanks :smile:

The membrane of a cell is electrically equivalent to a parallel plate capacitor. A typical cell has a spherical shape with a radius 10 μm and it has a potential of −60 mV with respect to outside. The thickness of the membrane is about 0.01 μm, and it has a dielectric constant of 2. Find: (a)...

I have no idea what principles i am supposed to use in this question? Could someone show me how to do this question please? Thanks :smile: Calculate the electrical potential energy of two protons separated by 1 nm, and compare it with their gravitational potential energy. Estimate how heavy...

I don't really understand Gauss' law - any help with this question would be appreciated? Coaxial cables are made of a copper wire in the center and a concentric cylindrical shell of copper outside, with insulating material in between and outside the shell. The charge per unit length of the...