5. Hydrogen Atom Energy Levels 

Rezaul Hasan Madame your analysis are very nice. date.29/08/22.

Too bad that she's not that awesome at what she's teaching, because there's a ton of misconceptions and incorrect information in these lectures.

​@@bonbonpony for example?

good catch

I was just looking at that, too... Came to the comments to clarify my sanity.

The molekular movement of molekules according to Brown make Molekules (especially big ones like Proteins) vibrate, translate or rotate. Since they dont hold still it is necessary to collect as many Photones as possible in a very short amount of time to get resolution data. Also CMOS-sensors (very common to use) need a certain amount of photons to generate any kind of analog signal. :) hope that helps

@@alangrey1916 that helps. Thanks!

Also the more intricate details of a protein crystal usually produce a lot of scattered beams in all sorts of directions with much lower intensity than the main ones. So you need a "brighter X-ray source" to notice those tiny beams too that usually are "too dark", and take them into account too. This makes up for a better quality of the data because you then have more information about the crystal structure. P.S.: There's a nice book about X-ray crystallography that I would recommend: "Principles of Protein X-Ray Crystallography" by Jan Drenth. It's quite easy to follow and everything is thoroughly explained, from the grass roots to more advanced topics, and contains not just raw theory, but also a lot of practical knowledge about laboratory techniques. It's a nice compendium about this subject.

?

emitted, it's a word

She puts a "D" in it ... like "idmission" sometimes she says Admitted and Admission... seems to be a speech anomaly for her. I must admit ...it drove me crazy.

Imo she is saying emmited.

on MIT OpenCourseWare. The link is in description.

lol that confused me so much, i had to check pronunciation videos cause i thought i may have been mispronouncing all these years

Should be "emitted". If only she knew the difference…

The itensity of a beam of light (x-rays here) is not related to the energy per photon. The itensity is related to the number of photons which are emmitted over a given time. Therefore if your x-ray source emmits only one photon per second the intensity is far lower than your x-rays would have if your source would emmit for example 1000 photons per second. This means that the power consumption of your x-ray source rises with the intensity but not because the energy per photon is higher but the number of photons is higher. => P = n*E_ph/t where P is the total Power, n is the number of photons emmitted by the source over the period of time t and E_ph is the energy a single photon is carrying.

@@universallappen1033 Thank you for the reply. Finally someone replied my question. It really helps.

@@RrNefriana you can ask me this kind of questions, I love to help people..... Try to spread knowledge.. Kami Khan from National University, Pakistan. #+923248507310

Yes but what she's referring to is the rydberg energy constant which has the formula Er=Rh(109677 cm^-1)*h(6.626*10^-34 js^-1)*c(3*10^8 ms^-1)

Which is roughly equal to =2.1798*10^-18 j

I just noticed that in my Chemistry (NCERT) textbook. It calls both of them as "Rydberg Constant" and doesn't even warn that both constants are different. In fact, it uses the same symbol for both constants (R with H as subscript)

@@aryanmediratta955 NCERT will also tell you that speed of light is equal to planck's constant if you allow them to ..

Congrats, this is literally just a reminder from high school though.

Then u dont understand what is the goal of said question. On exams and tests there will be plenty of tricky questions like this one. A lot less students would get confused after getting said questiom wrong as it will probably stay in their memory for a longer time rather than the teacher mentioning it

@@sds3841 Then those exams are equally bad. Instead of checking the understanding of chemistry, they check how good are you at picking nasty word tricks in questions. This has nothing to do with chemistry or physics. There are worse things in these lectures than just tricky questions though. They are full of misconceptions and straight out incorrect information stated as facts. There are numbers and tables used without proper citations. There are sloppy experiments that either do not demonstrate the phenomenon in question, or straight out demonstrate a completely different phenomenon from the one stated. The history bits presented are historically wrong. Famous scientists are being ridiculed or misquoted, and words are being put in their mouths that they never said or stated. There are tricks in calculations too that distort the view of the students about the results of the experiments (like, rounding a number in one place so that the result, after multiplying by 6, turned out to precisely match the experimental data, while in reality it should be not much closer to it than the previous calculations in which she used a non-rounded number). I could go on and on about how much things is wrong in these lectures…

You should apply for TA after you get a PhD in Chem and have 103840 years of experience.

From what I see, they also lowered the bar for teachers :q