Physics: Post your doubts here!

[papajohn]

Please can anyone solve me the question of Pacific book Volume 2 self evaluation 10.7 page no 278 Q:3. I tried very hard but cant solve it. Even the electrical engineer whom i give to solve cant solve it.

 

[sara kamal]

Please tell me how to calculate absolute errors when lg is present...where for eg R is 2+-0.2 and lgR is 0.3,whats erroe with 0.3??
i will be very thankful!

 

[Hassan Ali Abid]

Please tell me how to calculate absolute errors when lg is present...where for eg R is 2+-0.2 and lgR is 0.3,whats erroe with 0.3??
i will be very thankful!

Lg 2.2-Lg2.0 = error
Thats the way to calculate all the errors ..

 

[mm89mm]

For the first question, there is no work done in moving an object horizontally in air, so the work done is only against gravity, that is while moving the object vertically... so F* vertichal heigh = 20 kJ

For the second question, you have to keep in mind that velocity is a vector. Thus when it bounces of, it is in the opposite direction and the velocity you will use in your calculation will be -12.2... so

1/2 *.2 * (15.8^2 - (-12.2) ^2)

I didn't understand the vertical height = 20kJ and how is it possible that there is no work done while in the air in the horizontal direction?, would you please explain better if dont mind? And thanks for the reply,

 

[sara kamal]

Lg 2.2-Lg2.0 = error
Thats the way to calculate all the errors ..

Jazak Allah khair..!

 

[ahmed abdulla]

Can someone help with :
Question 6 (c)
& Question 12 (c)

 

[sma786]

Hey,
Does anybody want to do past papers with me? <3
AS past papers I mean
Inbox me!
xx

 

[Musab100]

A2 physics topical questions !!!!

 

[GlitteringLights]

hi i have a tiny doubt it the latest p2 paper
ques #2 part (a)
why have they done 0.8 x 10^-6 instead of 0.8 x 10^-3? ( aren't we supposed to convert from cm to m? or am i missing something )

 

[1357911]

hi i have a tiny doubt it the latest p2 paper
ques #2 part (a)
why have they done 0.8 x 10^-6 instead of 0.8 x 10^-3? ( aren't we supposed to convert from cm to m? or am i missing something )

to convert microfarad to meters.

 

[GlitteringLights]

to convert microfarad to meters.

isn't microfarad for capacitance? i hope u mean microsecond xD ok so u dont convert the 4 cm from the graph to m, u convert the time?

 

[1357911]

isn't microfarad for capacitance? i hope u mean microsecond xD ok so u dont convert the 4 cm from the graph to m, u convert the time?

oh. I dint look at the unit after micro. yeah its micro sec/// . Yeah u convert the time.

 

[GlitteringLights]

oh. I dint look at the unit after micro. yeah its micro sec/// . Yeah u convert the time.

haha kay thanks

 

[1357911]

http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s08_qp_4.pdf
Can anyone explain Q12 part b please?

 

[danial 234]

can any1 help me with mcq 21
http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w12_qp_13.pdf

 

[Iridescent]

What happens to the diffraction pattern if light does not strike normally to the grating?
Hassan Ali Abid

 

[danial 234]

hi i have a tiny doubt it the latest p2 paper
ques #2 part (a)
why have they done 0.8 x 10^-6 instead of 0.8 x 10^-3? ( aren't we supposed to convert from cm to m? or am i missing something )

the time taken by the pulse to travel whole distance is o.8 micro sec... or o.8 x 10^-6...
time taken to reach the reflector is o.4 micro sec
so d=3x10^8 x 0.4x10^-6 = 240 m ...
we wont convert cm into m ... cz the calibration and the time... both use cm... and cm will be cancelled while calculating time
1 cm= 0.2 micro sec
4 cm= 0.8 micro sec

 

[sara kamal]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s08_qp_4.pdf
Can anyone explain Q12 part b please?

formulas u will have to use..
attenuation=10 x log(P in/P out)
signal to noise ratio=10 x log (P out/P noise)
attenuation per uni length=total att/total lenth

do as follow
1 find power out......using secong formula.. 30=10 x log(p out/6.5x10-6) so p out=6.5x10-3W
2.find attenuation using formula 1 att=1o x log(26x10-3/6.5x10-3) so attenuation=6.02dB
3 finally find length using formula 3 length= 6.02/0.2=30 km

 

[goodluckayesha]

formulas u will have to use..
attenuation=10 x log(P in/P out)
signal to noise ratio=10 x log (P out/P noise)
attenuation per uni length=total att/total lenth

do as follow
1 find power out......using secong formula.. 30=10 x log(p out/6.5x10-6) so p out=6.5x10-3W
2.find attenuation using formula 1 att=1o x log(26x10-3/6.5x10-3) so attenuation=6.02dB
3 finally find length using formula 3 length= 6.02/0.2=30 km

for the 1st step the formula ok is understood then u make pout the subject then wht has to be done i dont get then how to get it plz elaborately explain the first step

 

[sma786]

A2 physics topical questions !!!!

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