Physics: Post your doubts here!

[princess Anu]

yeah i thought so too
but for Gravitational potential E don't we say energy stored in a mass due to its work done against the gravitational field ?

i think it's the first one; cause it's the energy stored right?

 

[nehaoscar]

yeah i thought so too
but for Gravitational potential E don't we say energy stored in an mass due to its work done against the gravitational field ?

Yeah true...I just define electric potential energy as the energy possesed by a charge when placed in an electric field (that's what i've been taught)

 

[princess Anu]

if the phase diff is 90 is it constructive or destructive interference?

 

[farhan141]

if the phase diff is 90 is it constructive or destructive interference?

Dest

 

[Mahnoorfatima]

http://www.sheir.org/a-level-physics-23-nov2013.pdf
Q4 bii ANYONE PLEASE!

 

[asadalam]

if the phase diff is 90 is it constructive or destructive interference?

Dest

Isnt it a bit of both?Total Dest will be on 180

 

[asadalam]

http://www.sheir.org/a-level-physics-23-nov2013.pdf
Q4 bii ANYONE PLEASE!

I did this by finding the time at t/2 and then applying relative equations to find height(GPE) and velocity(KE)Then you can find the ratios.

 

[princess Anu]

Isnt it a bit of both?Total Dest will be on 180

really? I'm confused
In the que I just posted , the waves have a phase diff of 90 degrees and in the next part they are adding their displacements to find the maximum displacement of resultant :s

 

[asadalam]

really? I'm confused
In the que I just posted , the waves have a phase diff of 90 degrees and in the next part they are adding their displacements to find the maximum displacement of resultant :s

I think we can find the relative change in phase difference with time using 1/8 x 360 = 45 so 45 degree change in every 1/8 of the period

Then you can draw the graph and find out the sums by adding.3/8 should be 90+135= 225

Again im not really sure about that question,whats the year?

 

[princess Anu]

I think we can find the relative change in phase difference with time using 1/8 x 360 = 45 so 45 degree change in every 1/8 of the period

Then you can draw the graph and find out the sums by adding.3/8 should be 90+135= 225

Again im not really sure about that question,whats the year?

yeah so we get a phase diff of 225, but what about the displacements? will they get added or subtracted to find the resultant displacement?

the book says its dec 2003/P3 but I' m not sure if its true.

 

[asadalam]

yeah so we get a phase diff of 225, but what about the displacements? will they get added or subtracted to find the resultant displacement?

the book says its dec 2003/P3 but I' m not sure if its true.

They are the algebraic sum.Just add the 2 points coinciding that will give the largest value.Draw a vertical line through both waves and identify one point where when adding together both waves displacement will give the largest displacement

 

[farhan141]

Anyone knows browning motion related questions in past papers?

 

[asadalam]

Anyone knows browning motion related questions in past papers?

Yes they can ask to draw apparatus,give conclusions as to what experiment shows and to explain why smoke particles are used and bigger smoke particles show little movement.

 

[nehaoscar]

How to define solids, liquids and gases and their spacing and also crystalline, polymer and amorphous solids? ... it came up in a paper once :/

 

[princess Anu]

I think we can find the relative change in phase difference with time using 1/8 x 360 = 45 so 45 degree change in every 1/8 of the period

Then you can draw the graph and find out the sums by adding.3/8 should be 90+135= 225

Again im not really sure about that question,whats the year?

Last question,
these waves have a constant phase difference,no? :s so even after 1/8T they should have the same phase diff :/

 

[asadalam]

Last question,
these waves have a constant phase difference,no? :s so even after 1/8T they should have the same phase diff :/

No they dont,as they are travelling in opposite directions hence their displacements will be different.Think of it like forming a stationary wave.At one time there will be large displacement where there is total constructive and at one there will be zero as there is total destructive.Getting me?

PS are my answers the right way to solve this?

 

[farhan141]

Yes they can ask to draw apparatus,give conclusions as to what experiment shows and to explain why smoke particles are used and bigger smoke particles show little movement.

Can u give an answer to all that u said? It would be really helpful.

Drawings and stuff as well

 

[Mahnoorfatima]

https://docs.google.com/viewerng/vi...wp-content/uploads/2012/11/9702_w14_qp_22.pdf
qs 2 ai? how do we know what values to take?

 

[nehaoscar]

https://docs.google.com/viewerng/vi...wp-content/uploads/2012/11/9702_w14_qp_22.pdf
qs 2 ai? how do we know what values to take?

Gradient of the graph remains the same (acceleration) so just extend the line keeping the gradient same

 

[princess Anu]

No they dont,as they are travelling in opposite directions hence their displacements will be different.Think of it like forming a stationary wave.At one time there will be large displacement where there is total constructive and at one there will be zero as there is total destructive.Getting me?

PS are my answers the right way to solve this?

Oh I understand now. Thanks a lot

btw, that means 90 degree phase diff can cause both constructive & destructive interference?
and the progressive waves that form a stationary wave ie the reflected nd incident waves have variable phase differences.. means they are not coherent, right?!

I'm posting the answer, you may check it from here.