Physics: Post your doubts here!

[robinhoodmustafa]

Please help me.
This a question from Mj 2004 and It says to draw a wave on the same diagram with double the intensity and 180 Phase difference but I am cofused with the (o.2,0.4) how can I know about the angles meaning Interpret these points on x axis as angles.. Hope you know what meant to say.
But do help me

 

[kathy nelson]

ASA
Can someone help me with this?
http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s09_qp_2.pdf
Question 5 part b
Thanks in advance

 

[robinhoodmustafa]

Please help me.
This a question from Mj 2004 and It says to draw a wave on the same diagram with double the intensity and 180 Phase difference but I am cofused with the (o.2,0.4) how can I know about the angles meaning Interpret these points on x axis as angles.. Hope you know what meant to say.
But do help me
View attachment 42208

 

[robinhoodmustafa]

ASA
Can someone help me with this?
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s09_qp_2.pdf
Question 5 part b
Thanks in advance

usama321
Hehe again this question

 

[robinhoodmustafa]

Yup i have it

Page 225
TestYourself Q12

 

[usama321]

Please help me.
This a question from Mj 2004 and It says to draw a wave on the same diagram with double the intensity and 180 Phase difference but I am cofused with the (o.2,0.4) how can I know about the angles meaning Interpret these points on x axis as angles.. Hope you know what meant to say.
But do help me
View attachment 42208

We know that a full wave has 360 degrees. 180 would be half of it. Furthermore, we also know that 180 means destructive interference which pretty much explains the whole question

 

[usama321]

Page 225
TestYourself Q12

For 12 a use d sin theeta = 2 lamda
for 12 b use d sin 90 = n lamda

 

[Haya Ahmed]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s06_qp_2.pdf

Q5 c can someone explain ! thanks ^^


and

Q7 (a) what do you mean by lamp is shortened

 

[Snow Angel]

t

at maximum point, the crest and crest meet: so displacement = 1.4+2=3.4 units
at minumum point crest and trough meet so displacement = 2-1.4=0.6
I is directly proportional to a²
so ratio of I = 3.4²:0.6² = 32.1
Snow Angel

thnx can u plz explain q 5 aii) from: papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w11_qp_22.pdf

why is it I1R2/2 and I2R2/2???

THNX IN ADVANCE. if u don mind me askin, which variant r u writing for all ur papers?

 

[zem]

B (i)

You can calculate the area by Box Counting method.
Find the area of an individual box between the two curve. Highlight small size boxes and multiply the total with the area of 1 box.

or another method is to assume the curve to be straight and apply the triangle area formula but I am not sure in this whether they have given a range in MS.
edit:
I found a useful site which shows a similar problem and he has assumed the curve to triangle.
http://tap.iop.org/mechanics/materials/229/page_46534.html
scroll down . and read the heading "Energy stored in stretched material"
because it said as long the object obeys hookes law than it is considered as a triangle. because u see the unloading part on question shows that it returns back to its orignal length

thanks alot!

 

[robinhoodmustafa]

We know that a full wave has 360 degrees. 180 would be half of it. Furthermore, we also know that 180 means destructive interference which pretty much explains the whole question

i know that but How do I Interpret that at this point the second and first wave has a PD of 180.
Like Turn 0.2,0.3,0.4 etc in angles* So that i may find it easy to locate 180 on the graph. That is what i am trying to say

further more..
If intensity is doubles than It means that Amp is 4 times increased ..right? *read the question*

btw Hey! I see my Name *imFamous*

 

[robinhoodmustafa]

For 12 a use d sin theeta = 2 lamda
for 12 b use d sin 90 = n lamda

The Calculating no of minima and maxima wala.

How did do know it would be sin teeta = 2 lamda.. is it written anywhere

 

[usama321]

i know that but How do I Interpret that at this point the second and first wave has a PD of 180.
Like Turn 0.2,0.3,0.4 etc in angles* So that i may find it easy to locate 180 on the graph. That is what i am trying to say

further more..
If intensity is doubles than It means that Amp is 4 times increased ..right? *read the question*

btw Hey! I see my Name *imFamous*

180 Phase difference equals one half of a wave. Just for your convenience, start the other wave after the half of the first wave, and then extend it to either sides. You will understand.
I = A^2 Amplitude here is 5. Put in the values get the amplitude double it and underroot

The Calculating no of minima and maxima wala.

How did do know it would be sin teeta = 2 lamda.. is it written anywhere

It says the second order.... second means 2 And we put in sin 90 to calculate the maximum number of orders. The light can't diffract more than 90 of course (according to my knowledge ) and thus when we put in 90 we get a decimal value of something around 5.7... Thus our answer would be 5

 

[Autumngirl]

I am confused about significant figures in paper 2. I've always been told to give as many significant figures in the answer as the least number in the data provided e.g. If data has both 2 and 3 significant figures, the answer must have 2 as it's the number in the least precise data. However, in the papers the mark scheme doesn't always follow this rule. Check out MJ11p23 question 3. Can somebody please explain why the examiners do this and give me a perfect rule about significant figures? Thank you!

 

[omaaaar]

http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s09_qp_2.pdf
Q7 full question don't understand how to do

 

[robinhoodmustafa]

usama321
Now check this question. It ask to draw a wave with PD of 60. and on x axis they have listed 1,2,3 etc so how do i know where angle 60 lies.

I understood the 180 PD one you told me earlier (Half the 360 one and start from there forward)

 

[ZaqZainab]

usama321
Now check this question. It ask to draw a wave with PD of 60. and on x axis they have listed 1,2,3 etc so how do i know where angle 60 lies.

I understood the 180 PD one you told me earlier (Half the 360 one and start from there forward)

View attachment 42228

360-3
60-0.5

 

[robinhoodmustafa]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s09_qp_2.pdf
Q7 full question don't understand how to do

First Part.
Resistance in Series : R+R...
Resistance in parallel : 1/R +1/R...


Second part.

Kirchhoff law.
Follow the Current direction and remember current divides in parallel and remain same in Series.
when is given part just focus on the direction he gives like " E2, I1 ,I2 and BCXYB part , forget about the other parts of the circuit like BYZA this way it would be easy to write down equation.
and read a bit about Kirchhoff from Book. It really helps

 

[robinhoodmustafa]

360-3
60-0.5

So a single complete wave.. only one wave end on 3 so it complete it on 360? and the complete(till 6) covers 720 degree??
and 60 how'd you find 60?

 

[ZaqZainab]

So a single complete wave.. only one wave end on 3 so it complete it on 360? and the complete(till 6) covers 720 degree??
and 60 how'd you find 60?

till 6 would be 2 waves and it would be 720
IF 360 is 3
then 60 is 0.5
cross multiply
3*60 /360