A2 Physics | Post your doubts here

[leadingguy]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w10_qp_43.pdf
http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w10_ms_43.pdf

mmm getting c as 4pie^2/GM whereas in markscheme its GM/4pie^2 explanation plz
c)i how to do :O and yea ii also

we have drived the eq. as T^2 = cr^3

just put the value of T and r in this eq. to find the canstant c use the frst colomn values.

then using this c and the r given i 2nd column calculate T


fr 2nd part we have time period T as o.165.

now frmua fr linear speed is v = rw

r is the radius given in question
w can be found out by using frmula..... 2π/T


u wil reach towards ur ans

 

[krazer36]

It said at a height o.5 above Earth's surface which means that r = R of Earth + 0.5 R(Height ABOVE Earth's Surface) = 1.5R
Hope you get it
shiningstar,

we have to find the gravitational field strength at 0.5r above the surface so total distance= 1.5r (because we add the total distance from the centre to the surface and the distance above the surface) so total distance = 1.5 x (6.4x10^6)
understand ?

Thank-you! =) I guess we assumed it to be 1r ... Because that is the only thing that was confusing me!

radius of earth might be 1 and the other thing is 0.5 above the earths surface...so total distance b/w them is 1.5...i guess

Lol You quoted the exact words which I had been thinking then ... Thank-you btw ...

 

[leadingguy]

Can someone explain to me what is line spectrum, emission spectrum and absorption spectrum? the difference?

In n11_41 Q 7)a) and Q7)c), please explain how to answer?

thanks in advance

line spectrum is the name given to the thing which is observed when the light emergent out frm the gas is having some dark lines.

trhese dark lines are the empty spaces fr the specififc energy photons which are abdorbed by the electrons of the gas. to reach to a higher level(excited state.)

 

[arlery]

http://www.xtremepapers.com/papers/...nd AS Level/Physics (9702)/9702_w10_qp_41.pdf
Ermm how should I plot the graph for Q 1b?

 

[leadingguy]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w10_qp_41.pdf
Ermm how should I plot the graph for Q 1b?

m not sure as the ans not given in ms rite???

so what i did was frst co-ordinate at (R, 1.0g) 2nd at (2R, 0.25g) thrd at (3R, 0.125g)


this is because the gravitaional frce is inversely proprtional to the square of r as we can see frm the frmula f = GMm/r^2

so doubling the distance by factr of 2 force wil be reduced to 1/4 times the graph wil be a curve

 

[arlery]

m not sure as the ans not given in ms rite???

so what i did was frst co-ordinate at (R, 1.0g) 2nd at (2R, 0.25g) thrd at (3R, 0.125g)


this is because the gravitaional frce is inversely proprtional to the square of r as we can see frm the frmula f = GMm/r^2

so doubling the distance by factr of 2 force wil be reduced to 1/4 times the graph wil be a curve

Ah THANK YOU!
What about c(i) of the same year? :S

 

[leadingguy]

Ah THANK YOU!
What about c(i) of the same year? :S

gravitational field is always attractive so lets take into consideration to positive charges ...

We know that two positive charges attract each other and there is a point in between these charges where the pottential is zero becuase the same work is done frm both charges at that point. or we can say that there is a neutral point here no field lins are present.


same is the case here ... both are attracting and if an objest is placesd in between these it wil experience a frce frm each of the body . thus there wil surely be a point where the frce of attraction frm one body at the object wil be the same as the frce frm the other at the object so both frces wil b canceeled out and zero wrk done (neutral point )

hope U gt it

 

[arlery]

gravitational field is always attractive so lets take into consideration to positive charges ...

We know that two positive charges attract each other and there is a point in between these charges where the pottential is zero becuase the same work is done frm both charges at that point. or we can say that there is a neutral point here no field lins are present.


same is the case here ... both are attracting and if an objest is placesd in between these it wil experience a frce frm each of the body . thus there wil surely be a point where the frce of attraction frm one body at the object wil be the same as the frce frm the other at the object so both frces wil b canceeled out and zero wrk done (neutral point )

hope U gt it

Ohh okay, wow you made it SO easy!
Thank you.

 

[angelicsuccubus]

Can someone explain to me what is line spectrum, emission spectrum and absorption spectrum? the difference?

In n11_41 Q 7)a) and Q7)c), please explain how to answer?

thanks in advance

The light radiated when electrons emit quanta of photons is called the emission spectra. There are three types of emission spectra:
1. Light spectrum- a series of bright lights produced by isolated atoms (atoms which have negligible intermolecular forces)
2. Band spectrum- when there is interaction between atoms, a greater number of energy levels is available so a band spectrum is produced.
3. Continuous spectrum- when atoms are close together, all energy levels within a range are available so all frequencies of light within a range are emitted and a continous spectrum is produced.

Absorption spectrum- frequencies corresponding to transitions (the jumping of electrons between energy levels) are absorbed by the atoms so the emission spectrum has dark lines for those frequencies. That's an absorption spectrum.

 

[user]

assalamoalaikum wr wb!

http://www.xtremepapers.com/papers/...nd AS Level/Physics (9702)/9702_w09_qp_41.pdf

Q:8 c ii why do we take 17.7 negative?

 

[princesskt]

http://www.xtremepapers.com/CIE/ind... Level/9702 - Physics/&file=9702_s02_qp_4.pdf


help.............plz

draw the graph for q6..................plz

 

[user]

http://www.xtremepapers.com/CIE/index.php?dir=International A And AS Level/9702 - Physics/&file=9702_s02_qp_4.pdf


help.............plz

draw the graph for q6..................plz

 

[princesskt]

View attachment 9491 View attachment 9490

current is alsa varrying like but on positive site......

 

[KaiserFury]

http://www.xtremepapers.com/CIE/International A And AS Level/9702 - Physics/9702_s03_qp_4.pdf

Can anyone, please, explain to me number 2 (B)? The silver and gold question.

 

[princesskt]

View attachment 9491 View attachment 9490

can u just explain me wts the phase d/f b/w current and emf in primary
and in secondary............

 

[angelicsuccubus]

http://www.xtremepapers.com/CIE/index.php?dir=International A And AS Level/9702 - Physics/&file=9702_s02_qp_4.pdf


help.............plz

draw the graph for q6..................plz

they were talking about that graph, all over the thread.. go back to the first 40 pages or so

 

[princesskt]

they were talking about that graph, all over the thread.. go back to the first 40 pages or so

ok thanx..........

 

[angelicsuccubus]

If there is anyone here who's got quick notes to the direct sensing, medical imaging and communications systems chapters.. please upload them.. I have got to sleep ... its been over 38 hours!

 

[arlery]

If there is anyone here who's got quick notes to the direct sensing, medical imaging and communications systems chapters.. please upload them.. I have got to sleep ... its been over 38 hours!

Check out Mathy's A2 physics notes!

 

[arlery]

http://www.xtremepapers.com/papers/...nd AS Level/Physics (9702)/9702_w10_qp_41.pdf
In Q 2 b (iii) How can I get 840 for the work done on gas for R -->P? :S