Physics: Post your doubts here!

[1357913579]

Assalamoalikum Wr Wb
http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w09_qp_42.pdf
number-12c(i) please dra graph for it
thanks and Jazak Allah Khairn

 

[1357913579]

Challenge For Every one :S

I have posted the solution of this question before as well
see first off all when the lift moves 1mm down each of the steel cable expand with an extention of 1mm.
-the downward force by man is (80)(9.81)=784.8N
-this is the sum of the force applied to those 2 steel cables
- as both have the same dimention they will experience the same force
- 2f=784.8 where f is the force experienced by one steel cable
-f=392.4
-young modulus=fl/eA
-A=pi(0.25x10^-2)2=1.96x10^-5 m
-length is given
-extension is given convert it to meter
-plugin in the point you'll get the answer.

 

[Tkp]

View attachment 23390

check out this thread.u will get the ans

 

[Dug]

sm1 plz help wid dis qs
(b) An electron is accelerated from rest in a vacuum through a potential difference of 4.7 kV.
(i) Calculate the de Broglie wavelength of the accelerated electron.
wavelength = ............................................ m [5]
(thid qs is frm w12-43)

W = QV
W = (1.6 x 10^-19)(4.7 x 10³)
W = 7.52 x 10^-16

W = KE = ½ mv²

7.52 x 10^-16 = ½ (9.11 x 10^-31)(v²)
v = √(2)(7.52 x 10^-16)/(9.11 x 10^-31)

λ = h/mv
= Ans

 

[gary221]

Assalamoalikum Wr Wb
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w09_qp_42.pdf
number-12c(i) please dra graph for it
thanks and Jazak Allah Khairn

 

[Warrior66]

View attachment 23335

i think the answer's D?? (obviously you need to write the actual answer as well in order for me to know if i have got it right and only then would it make sense that i explain how i got it..)

 

[Malik777]

i think the answer's D?? (obviously you need to write the actual answer as well in order for me to know if i have got it right and only then would it make sense that i explain how i got it..)

A

 

[hassankhan]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/
Plz someone help me with question 5 part c.... thnks

 

[1357913579]

A

obviously A
-the vertical component of 20 is 20cos(theata) and its horizontal component is 20sin(theata)
-hence F=20sin(theata) and 15=20cos(theata) IF the system is in equilibrium

 

[taimoor.08]

can anyone help me with these two questions
with working
thnk u in advance

the answer is C .we should first calculate total resistance which is about 0.59 .From V=IR ,voltage can be calculated which is same throught the circuit.so by V=IR it can easily be calculated

 

[1357913579]

i have doubt in this question i have drawn the graph below and i think thiere is some mistake in this can some one please check and if theres a mistake rectify it please
http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_w07_qp_4.pdf
question number-10(c)
and my attached solved

 

[cyclone94]

What is the meaning of SHM? and what is Angular Frequency?

SHM(simple harmonic motion)-motion of an oscillator where it's acceleration is directly propotional to it's displacement from it's equilibrium position and is directed towards dt position.
Angular frequency-the rate of change of angle expressed in radian per second.

 

[salvatore]

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_s12_qp_22.pdf
Could someone please help me solve qn no. 2 (b)? I'll really appreciate if you could sketch the graph for me..

Thanks!

 

[ahmed abdulla]

check out this thread.u will get the ans

can some one help me with how to find PHASE DIFFERENCE between two points on same wave ... and how to draw a wave if eg .said another wave has phase difference 90 degree .... ??


questions like this can be found here >>http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w11_qp_23.pdf qp 5c(i 2)

 

[Tkp]

can some one help me with how to find PHASE DIFFERENCE between two points on same wave ... and how to draw a wave if eg .said another wave has phase difference 90 degree .... ??


questions like this can be found here >>http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w11_qp_23.pdf qp 5c(i 2)

a=2.8(check the graph)
m nt good at this part but i will try
frm its max amp to b the phase difference is 90 and fr a to max the phase difference is 1/2 of 90
so phase diff is 135

 

[Areeba Shahnawaz]

One property of
α
-particles is that they produce a high density of ionisation of air at
atmospheric pressure. In this ionisation process, a neutral atom becomes an ion pair. The
ion pair is a positively-charged particle and an electron.
The energy required to produce an ion pair in air at atmospheric pressure is 31 eV.

An
α
-particle has an initial kinetic energy of 8.5 × 10

–13
J.
(i)
Show that 8.5 × 10 –13J is equivalent to 5.3 MeV???
can anybody prove this? its Q7 of June 2010 Variant 23

 

[ahmed abdulla]

a=2.8(check the graph)
m nt good at this part but i will try
frm its max amp to b the phase difference is 90 and fr a to max the phase difference is 1/2 of 90
so phase diff is 135

thanks ... if some one has a better idea .....any help ???

 

[Alool]

Can someone please help me with this question?
this is from M/J 2008 p2

 

[Warrior66]

A

ok..so i tried it again and i happen to get A as well..here's my explanation:
basically what we do is we use all the vectors given to make a closed triangle since the question tells us that the object is in equilibrium.

so now you try out all the options with the triangle above and you find out your answer is A.

 

[Tkp]

Can someone please help me with this question?
this is from M/J 2008 p2

for the first 1 p=v^2/r(put the value of v and p which is in kw)
fr 2nd 1 when s1 is open and s2 and s3 is closed then the power would be zero due to the open of s1.
when s1 and s2 closed and s3 open then the power would be 1.5 becz due to the close of s2 so the power would be 1.5
when 3 of them are closed then the total power is 3 becz due to the close of s2 we get 1.5 and through s3 its 1.5 so total is 3
when s1 closed and s2 and s3 open then the power would be 0.75
s1 closed s2 open s3 closed,so the power of s3 is 1.5 and due to the open of s2 the power would be 0.75
s0 total power is 2.25