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Physics: Post your doubts here!

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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)
 
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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.
 

Dug

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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
 
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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 :)
 
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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.
 

Tkp

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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
 
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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
 
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