ALL CIE PHYSICS DOUBTS HERE !!!

[astarmathsandphysics]

No relation between drag and upthrust or weight.
It depends on the board, but you may need to know Stoke's law.
Drag=resistance
upthrust=weight for a floating body - this is Archimedes principle

F=ma=m(dv/dt)=m(dx/dt)(dv/dx)=mv(dv/dx)
hence Fdx=mvdv
integrate both sides to get Fx = mv^2/2
For Kirchoff's laws the proof is here
http://www.astarmathsandphysics.com/a_level_physics_notes/electricity/a_level_physics_notes_resistivity_and_resistance.html

[minicooper]

Theeank eeou!

[astarmathsandphysics]

Bno probs

[cs]

Please and thank you

[astarmathsandphysics]

will have to be tonight

[astarmathsandphysics]

Because the forces act on AB and CD

[ashwinkandel]

Question from Chapter==> Superposition of Waves
Q.
Figure 1 shows the set up used to analyse the spectrum of a sodium discharge lamp using a diffraction grating with 5000 lines/cm . Figure 2 shows the developed photographic  film showing the spectral lines observed.
Look Fig 1 and 2 and answer
i. Explain why two spectra are observed.
ii. Study the two spectra and describe two differences between them.
iii. The green maximum near end A is at an angle of 15.5 degree. Calculate the wavelength of green light.
iv. Calculate the angle produced by second green light.[stream=475,325][/stream]

[astarmathsandphysics]

i)two spectra are displate because of the diffraction grating equation sin theta = n*wavelength/a.
For each wavelength multiple spectra are produced n=1.2.3 etc
ii) one is more spread out than the other. The spectrum on the left is brighter than the one on the right.
iii)sin theta=n*wavelength/a
sin 15.5=1*wavelength/(0.01/5000) so wavelength=sin (15.5)*0.01/5000=5.34*10^-7 m
iv)sin theta = 2*5.34*10^-7 /(0.01/5000) =0.53 so theta =sin^-1 0.53 =32.3 degrees

[ashwinkandel]

Shouldn't the value of n in question no. iii. and iv. be 3 and 8 respectively??

[astarmathsandphysics]

No. It is 1 for each colour, then 2 for each colour.

[ashwinkandel]

I recently encountered same kind of question in the past papers. Can you give me the clarification of the answer of ii. .

[SZM]

here ashwinkandel, since u r doing alevel cambridge. i am sure, u must have small experience towards alevel stuffs. U r from where?? I am from Sri-Lankan.

hve u heard anything about tmisterr and MKH?? Pls let me know if u hve heard about them??? becoz after so many days, i havent seen their online/// why is dat??? ow cn i contact them?? becoz i found their helpful really useful, thaty. and i need to discuss with them some small sort of problem. So anyone pls let me know what has happened these two members?? I was looking or their online. but unfortunately they r offlined?? pls tel  me , ow to contact them?

I am doing alevel edexcel privately not schooling, so pls help me.


i thought of doing self study, but i am not studying anything, becoz i am thinking all the time, how to start and where to start and how to speed up, which is said to be nonsense. I am being really stupid . But i like to self study, but it doesnt come. I have potential to self study, but it still doesnt work or doesnt come naturrally. i dont know why?

I have read different thread, where some member has mentioned, that to do exam well and get best grade, answering techniques are very very important and we must improve that very well. Then i thought, if i do self study and after finish studying, whn i do pastpaper, then i will go thru markschemes and then mark . But that is not enough, becoz marking scheme gives only point form. SO i hve to go for classes to ask teacher how to start the answer and how to end up and to start and end, there must be the meaning and there should be a logical sequence. So these kind of style of writing is very important in the exam. Am i correct??? Teachers always tel us, that the best answers are short and precise. wat does that mean?? why cant i write long, if i want to explain further, wiil the examiner get angry or wat?? how to improve that?? for example the suggest questions, i cannot write short and precise, i will write a bit more// is that gud or bad??? pls tel me dear. i need ur reply tho this matter.

1.My mother told me it is not necessary to attend the class ALWAYS... She told me at the beginning, it is a must to attend, after some few classes, like each subject 3 /4 times attending classes, u will get the potential to do self study after having idea from the tutor how to manage with//// Is dat true or will that work>>>

2.my idea is , i collect the concepts , that i found difficult to understand in all units and then whn i go for class, i cn ask the tutor to explain in details, the doubts i have inorder to clear them within 2 and half hours. wat do u think??

3.or should i attend the class from the beginning till i complete the syllabus. till dat i have to attend the classes. is dat so or not? pls tel me.. I am worried, becoz with difficulty i found the classes and make the time. afterall if i dont attend, then they wont take me ,whn i need to go for classes. SO i dont want to waste the time and i dont want to get stuck at the last moment or last minute. I should be very careful. so therefore pls tel me ur suggestion to this matter... I am really worried about that. Thats all i want from ur suggestion .pls help me dear.

But i must not waste the time even for a minute.

waitn for ur reply. need ur reply urgenlty.

[ashwinkandel]

Hello SZM I am from Nepal doing CIE A level. I am not learning privately.I go to college. I think your question can be better answered by astarmathsandphysics as he has been tutoring A level students since 10 years.

[SZM]

but ashwinkadel, i have sent this questions under QUERIES, but he has not answered for about 3 days.... I am worried about that.

By the way nice to hear about u. When are u going to do final exam ? Both AS and A2?

I just want from ur suggestions, is self study suitable for alevel? I mean 75 percent self study and 25 percent from teachers Help..

wat do u think??

need ur reply urgrnlty

[ashwinkandel]

I am giving my AS exams now. Already given 4 papers 6 remaining.Self study is perfectly suitable for theory part but for practicals part.... What will u do?