Author Topic: ALL CIE PHYSICS DOUBTS HERE !!!  (Read 151801 times)

Offline NidZ- Hero

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Offline EMO123

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #796 on: June 07, 2011, 06:10:44 pm »
I know the answer But i want An explanation Can Some one explain

http://www.xtremepapers.me/CIE/International%20A%20And%20AS%20Level/9702%20-%20Physics/9702_w07_qp_1.pdf

Question 11, 16 , 17 , 26
11.
Equal and Opposite Force Exerted on Road by the wheel so the answer is B

16.
The there is a elastic Potential Energy it is maximum at Position 3
and kinetic energy is minimum because when Potential Energy is Maximum then the K.E. is minimum.

17.
The density of the substance (x cm^3) = Density of the same substance (of unit volume)
       Keeping this in mind, density = mass/volume

        Mass of an atom = Mp, there Np atoms in all

        Thus, mass of Np atoms = Mp*Np

        Volume = unit volume
Density of P = (Mp*Np)/unit volume
Repeat the same with Q, density = (Mq*Nq)/unit volume
As density of P > density of Q
Mp*Np > Mq*Nq
(Unit volume gets cancelled)

26.
as Shown in the diagram that the field is moving from Positive to Negative
so if the electron is placed there then it will definitely the the right so
it will move towards the left

Hope it Helps
« Last Edit: June 07, 2011, 06:16:39 pm by EMO123 »

Offline Ghost Of Highbury

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #797 on: June 07, 2011, 06:24:42 pm »
http://www.xtremepapers.me/CIE/International%20A%20And%20AS%20Level/9702%20-%20Physics/9702_s09_qp_1.pdf
q 20

Stress = tension/area
Tension = stress*Area
stress = Y*strain
Tension = Y*Strain*Area
strain = e/l
Tension = YeA/l
Tension (P) = YeA/l
Tension (Q) = Ye0.5A/2l = YeA/4l
Tension(P)/Tension(Q) = 4/1
divine intervention!

Offline Ghost Of Highbury

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #798 on: June 07, 2011, 06:27:57 pm »
I know the answer But i want An explanation Can Some one explain

http://www.xtremepapers.me/CIE/International%20A%20And%20AS%20Level/9702%20-%20Physics/9702_w07_qp_1.pdf

Question 11, 16 , 17 , 26 , 37


http://www.xtremepapers.me/CIE/International%20A%20And%20AS%20Level/9702%20-%20Physics/9702_w08_qp_1.pdf

Question 27 , 29

http://www.xtremepapers.me/CIE/International%20A%20And%20AS%20Level/9702%20-%20Physics/9702_s07_qp_1.pdf

Question  40 , 37


http://www.xtremepapers.me/CIE/International%20A%20And%20AS%20Level/9702%20-%20Physics/9702_s08_qp_1.pdf

Question 14 , 16 , 31

THANNNNNKS


w08 - 27) Distance b/w 2 antinodes = 15mm
                 wavelength = 15mm*2 = 30mm = 0.03m
Frequency = c/wavelength = (3*10^8)/0.03 = 1*10^10
29) THe point charge is positively charged. SO inwards. Force on X > Y , because its closer
divine intervention!

Offline EMO123

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #799 on: June 07, 2011, 06:33:25 pm »
http://www.xtremepapers.me/CIE/International%20A%20And%20AS%20Level/9702%20-%20Physics/9702_w08_qp_1.pdf

Question 27 , 29
27.
The Frequency of Microwave is 1*1010 if you have got the graph then see in that
so the answer is C

29.
as the field strength is moving from positive to negative that is from center to outwards
so the and X is more near to the Center so Magnitude of force on X is Greater Than on Y
and radially inwards as explained
so the answer is B

Offline NidZ- Hero

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #800 on: June 07, 2011, 06:55:24 pm »
11.
Equal and Opposite Force Exerted on Road by the wheel so the answer is B

Y not A

Offline Ghost Of Highbury

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #801 on: June 07, 2011, 08:02:35 pm »
I'm off, good luck for tomorrow guyz. Hope you all do well. :D
divine intervention!

Offline EMO123

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #802 on: June 07, 2011, 08:03:57 pm »
I'm off, good luck for tomorrow guyz. Hope you all do well. :D
thanxx and good luck to all of us

Offline physichemaths

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #803 on: June 07, 2011, 09:06:35 pm »
Hai guys. How to get the answers for nov08 ques 1?

Offline SkyPilotage

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #804 on: June 07, 2011, 09:32:11 pm »
Hai guys. How to get the answers for nov08 ques 1?
Speed of light = 3x10^8 ms^-1
So Number of wavelength/second = frequency= speed/wavelength..

Offline EMO123

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #805 on: June 15, 2011, 01:53:23 pm »
May/June 2007
Paper 04

Q-2 c)
Q-3 b)
Q-4

more doubts coming from me soon

Offline $H00t!N& $t@r

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #806 on: August 28, 2011, 12:10:25 pm »
Please help me out with the following questions:

1) Two satellites orbit a planet of mass 'M' with Time periods of 3 days and 4.5 days, respectively. If the orbital radius of the first satellite is 2x10^6 m, determine the radius of orbit of the other. (Answer is 2.62x10^6)

2) A mass 'm' is moved from the North pole towards the equator. If the Earth is assumed to be a perfect sphere of radius 'R' , and if the mass moved is exactly 60kg, determine the difference in weight when measured at the North pole and at the equator.
R = 6.4x10^6 m
M of Earth = 6.0x10^24 kg
G = 6.67x10-11
m = 60 kg
    ( Answer is 2.0 N )

3) An astronaut travels from the Earth towards the moon where he experiences no net force. Determine the distance from the surface of the moon where this phenomenon occurs. Given that,

- the radius of the moon is 1.74x10^6 m
- mass of the moon is 0.0735x10^24 kg

(Answer is 3.71x10^7 m )

Please help me out.. i desperately need the explanation for these quesitons...
« Last Edit: August 30, 2011, 09:46:15 am by $H00t!N& $t@r »
"If A equals success, then the formula is:
A=X+Y+Z, X is work. Y is play. Z is keep your mouth shut"- Albert Einstein

Offline tmisterr

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #807 on: August 28, 2011, 03:22:34 pm »
Please help me out with the following questions:

1) Two satellites orbit a planet of mass 'M' with Time periods of 3 days and 4.5 days, respectively. If the orbital radius of the first satellite is 2x10^6 m, determine the radius of orbit of the other. (Answer is 2.62x10^6)

2) A mass 'm' is moved from the North pole towards the equator. If the Earth is assumed to be a perfect sphere of radius 'R' , and if the mass moved is exactly 60kg, determine the difference in weight when measured at the North pole and at the equator. ( Answer is 2.0 N )

3) An astronaut travels from the Earth towards the moon where he experiences no net force. Determine the distance from the surface of the moon where this phenomenon occurs. Given that,

- the radius of the moon is 1.74x10^6 m
- mass of the moon is 0.0735x10^24 kg

(Answer is 3.71x10^7 m )

Please help me out.. i desperately need the explanation for these quesitons...


hello  :)

1. gravitational force = centripetal force. once we know that...we have solved the question.

   GMm/r2=mv2/r
where M is mass of planet and m is mass of satellite. since they orbit the same planet, M is equal in both cases.

now we know that v= 2*pi*r/T where 2*pi*r is the circumference of orbit and T is the periodic time (easy, velocity=distance/speed). so next we play around with the above equation... It is not difficult to see that

M= 4*pi2*r3/GT2

Voila...so now we plug in the data values of planet 1, converting days into seconds and the value of gravitational constant G (6.67x10-11) to get the value of M as 7.04....x1019

Ok so now we play around with the equation for M to make r the subject of the formula...easy enough.

We know T for the second planet is 4.5 days (don't forget to convert to 4.5*24*3600 seconds) and we now know that M is 7.04...x1019. simple arithmetic............r is (to be exact lol) 2620741.394 m but due to rules of accuracy we quote it to 3 s.f hence 2.62x106[/sup

Offline tmisterr

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #808 on: August 28, 2011, 03:31:51 pm »
on so once you got the concept...we can save time doing all those arduous calculations.
all we need to see is this:

M=4*pi2*r3/GT2

and since M is the same for both planets, we can replace this equation directly into the equation of R (radius of second planet)

to get R=cube root( T2r3/t2)
try deriving for yourself

where T is the period of planet 2 (4.5 days converted to seconds), r is the radius of planet 1 (2x106) and t is the period of planet 1 (3 days converted to seconds)

I'm sure you'll find this saves a lot of time :)

Offline $H00t!N& $t@r

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Re: ALL CIE PHYSICS DOUBTS HERE !!!
« Reply #809 on: August 28, 2011, 04:33:09 pm »
i love u mannn!  :D thanks alott
"If A equals success, then the formula is:
A=X+Y+Z, X is work. Y is play. Z is keep your mouth shut"- Albert Einstein