Physics: Post your doubts here!

[Browny]

http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s09_qp_2.pdf

In question paper 21 can anyone explain Q)5) especially part b)?

 

[_Ahmad]

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w11_qp_22.pdf
Can anyone please explain Q5 a ii) and iii)

 

[Autumngirl]

Is it important to know how to draw leading and lagging phase difference? Nowadays they just ask phase difference but in 2002 they asked for lagging which I don't really understand.

 

[Jelleh Belleh]

Need help please. what are up and down quarks??

Why do you want to know about quarks?? They aren't in the syllabus. Did you see a question on them?

 

[kitkat <3 :P]

Kindly someone answer mine pleaseeeee ???

whats the answer m getting 22.6 ;/

 

[DeViL gURl B)]

at A the phase angle is 45 at B its 180
so phase difference will be 180 -45 that is 135

Oooohh .. That was easy

 

[TheJDOG]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w11_qp_23.pdf

Question 5 c(i) 2.
I'm getting 270 degrees..
But the answer is 135 degrees :$
Please explain.

Hello there, first we know that 1 Wavelength = 360 degrees, look at the graph, you'll see that 1 wavelength is 8 blocks.

Blocks between A and B are 3 blocks.

Cross multiply,
360-----> 8 blocks
?----------> 3 blocks


You'll get phase difference between A and B is 135 degrees

 

[Ahmed Aqdam]

Umm umm I cant make out! it must be correct

The time period of the stationary wave is 20ms. After 5 ms, it would be a straight horizontal line, drawn on the dotted line. Take a look at this animation and you will understand the logic

usama321

but why would be a straight line after 0.005 s? please can u xplain. thnx

Look at this post.

 

[Thought blocker]

*COUGHED*

 

[omaaaar]

http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s07_qp_2.pdf
Q5 b complete

 

[DeViL gURl B)]

Hello there, first we know that 1 Wavelength = 360 degrees, look at the graph, you'll see that 1 wavelength is 8 blocks.

Blocks between A and B are 3 blocks.

Cross multiply,
360-----> 8 blocks
?----------> 3 blocks


You'll get phase difference between A and B is 135 degrees

Gotcha! I didn't actually see the graph properly.. I was takin it as 4 blocks..
But thank you!!
Plus we can apply the equation as well right.. (X/wavelength *360)

 

[Usman Chughtai]

whats the answer m getting 22.6 ;/

This is the mark scheme answer I couldn't solve it

 

[Browny]

http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s09_qp_2.pdf

In question paper 21 can anyone explain Q)5) especially part b)?

 

[kitkat <3 :P]

This is the mark scheme answer I couldn't solve it

i got it look
the horizontal line given is 7 cm
so scale is 4ms^-1 = 7
so 1 ms^-1 =1.75 cm
vertical velocity is 6.2
draw the resiltant it will be 7.4
do u want me to post the diagram but its not neat ?

 

[Usman Chughtai]

i got it look
the horizontal line given is 7 cm
so scale is 4ms^-1 = 7
so 1 ms^-1 =1.75 cm
vertical velocity is 6.2
draw the resiltant it will be 7.4
do u want me to post the diagram but its not neat ?

Oh thanks a lot
would appreciate if u could post it here or Inbox me

 

[TheJDOG]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s07_qp_2.pdf
Q5 b complete

Hello there, for B I)
We know that there is a stationary wave in that tube.
At antinodes which are maximum displacement, the wave pushes the heaps apart.
At nodes which are minimum displacement, the heaps are formed
This forms the dust heaps.

For B Ii)

Look at the figure, you'll see that the distance between 6 heaps is 0.39 meters

We know that this stationary wave's wavelength at these heaps is 2.5 Lambda.
Because it has Compression-Rarefaction-Compression and so on.
One wavelength is from C to C or from R to R.

We know Freuquncy F= 2140 Hz

We know speed of wave equation V= Lambda x F


We need 1 lambda and not 2.5 lambda so we need to convert.

0.39 m-----> 2.5 lambda
? ------------> 1 lambda

It's 0.156 m

So V= 2140 x 0.156=334m/s


Iii)
Stationary waves is formed by interference of incident and reflected waves
the speed is the speed of the incident waves

 

[Thought blocker]

I am on!

 

[DeViL gURl B)]

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w10_qp_22.pdf

Question 6 complete PLEASE!!!
Especially the b part!!! :$

 

[IGCSE13]

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_s13_qp_23.pdf. Q6 ci pleaseeee help

 

[omaaaar]

Hello there, for B I)
We know that there is a stationary wave in that tube.
At antinodes which are maximum displacement, the wave pushes the heaps apart.
At nodes which are minimum displacement, the heaps are formed
This forms the dust heaps.

For B Ii)

Look at the figure, you'll see that the distance between 6 heaps is 0.39 meters

We know that this stationary wave's wavelength at these heaps is 2.5 Lambda.
Because it has Compression-Rarefaction-Compression and so on.
One wavelength is from C to C or from R to R.

We know Freuquncy F= 2140 Hz

We know speed of wave equation V= Lambda x F


We need 1 lambda and not 2.5 lambda so we need to convert.

0.39 m-----> 2.5 lambda
? ------------> 1 lambda

It's 0.156 m

So V= 2140 x 0.156=334m/s


Iii)
Stationary waves is formed by interference of incident and reflected waves
the speed is the speed of the incident waves

Can you explain how did you get the wavelength as 2.5 lambda