Physics: Post your doubts here!

[ZainH]

http://www.xtremepapers.com/papers/...and AS Level/Physics (9702)/9702_s07_qp_2.pdf
Q6b)ii)

They used the derived formulae to calculate the energy, E=I^2*R*T

I know how its derived, P = I*V , V=I*R so
We can write P=I*I*R

Since P=E/T , we can write E/T=I*I*R
which can be simplified to E=I^2*R*T

Instead of using the derived formula I use two different formulas, P=I*V first which gives me, 150W
Then I use P=E/T , which gives me 150*4*3600 = 2160000Joules which is a different answer then the one we get while using the derived equation. How come?
Am I doing something wrong .____. ?

 

[ZainH]

NVM , I'm an idiot. Was looking at the wrong part of the mark scheme -_______________-

 

[BettyBoop]

answer is B can someone explain

 

[BettyBoop]

ans is A
and this please help someone!!

 

[Sriyog Sharma]

Need help .

 

[Sriyog Sharma]

View attachment 18653ans is A
and this please help someone!!

Use the formula, Force-Friction=mass * acceleration.
Force will be the the weight of the load that is pulling 8 kg load . now the F=2*9.81 =19.62 N
now Friction we are given which is 6.0 N.
now we are calculating the system's acceleration , so , the mass will be (8+2 ) =10 kg.
now ,
19.62 - 6 = 10 * acceleration
acceleration = 1.362
which is 1.4 m/s2

Can you please see this question that i have attached !

 

[autumnsakura]

http://www.xtremepapers.com/papers/...nd AS Level/Physics (9702)/9702_w09_qp_12.pdf
Q12,13,14 thanks!!

 

[autumnsakura]

Use the formula, Force-Friction=mass * acceleration.
Force will be the the weight of the load that is pulling 8 kg load . now the F=2*9.81 =19.62 N
now Friction we are given which is 6.0 N.
now we are calculating the system's acceleration , so , the mass will be (8+2 ) =10 kg.
now ,
19.62 - 6 = 10 * acceleration
acceleration = 1.362
which is 1.4 m/s2

Can you please see this question that i have attached !

I think answer should be D. When the liquid moves up the right tube, it actually moves down the left at the same distance. So for example, your right tube liquid increase by 10, your left tube decrease by 10. The h difference between both tubes is actually 20 which is twice of the actual distance moved...

 

[Sriyog Sharma]

I think answer should be D. When the liquid moves up the right tube, it actually moves down the left at the same distance. So for example, your right tube liquid increase by 10, your left tube decrease by 10. The h difference between both tubes is actually 20 which is twice of the actual distance moved...

Can you please explain me how the h difference will be 20 ?? wont it be 10 ?

 

[Rickster]

could you help me with some questions please.
Q4
Q23( Is it because E is the same no matter what the dimensions are?)
Q26
Q33
Q34

http://www.xtremepapers.com/papers/...nd AS Level/Physics (9702)/9702_w11_qp_11.pdf

Thanks a lot​

 

[Alice123]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s12_qp_11.pdf: Q8,12,24 n34
http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s12_qp_12.pdf:Q17, 18, 30, 32 n 37
plssss help!

 

[Farru]

http://www.xtremepapers.com/papers/...and AS Level/Physics (9702)/9702_s08_qp_1.pdf

ques no.24, and 26 plsss!!

 

[Sriyog Sharma]

need help!

 

[queen of the legend]

you can solve this question in two ways : (2nd is recommended)
at first we know that X= lamda x d / a , so apply it for the first equation and take d=1

1 x10^-3 = 600 x 10 ^-9 x 1/ a a= 0.6 mm

in the second equation we knw that x = 3mm and d increses by 2 ..so notice that "by'" and "to" is in bold

1+2 = 3 m .......... so 3 x 10^-3 x a = 600 x 10 ^-9 x 3 again you get 0.6 mm

 

[raamish]

n10 12: qs 8(my answer is coming 0.49ms-2) can any1 help me plzz

 

[queen of the legend]

[quote="Farru, post: 4 1.pdf

ques no.24, and 26 plsss!![/quote]
in 24 the answer is E since young modulus is property of material and the material stays the same so E is constant ...its a tricky question !
for 26: since I is proportional to a^2/x^2 ..... so increasing x by 2 gives us 4x^2 ....since x increases by 4 I decreses by 4 and hence amplitude decreses by 4 ......so you get 8-4 = 4µm

 

[hussamh10]

View attachment 18652answer is B can someone explain

first find the distance between tge screen and double slit the (d) so we get two equations
x=d x lamda /a
making a the subject
so a=d x lamda /1x10^-3 and 2nd equatiom we get a=(2+d) x lamda/3 x 10^-3
solving them simultaneously we get D and the put d in any equation and we get (A) fringe seperation note that A is constant ....

 

[geek101]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s08_qp_1.pdf

ques no.24, and 26 plsss!!

24) the youngs modulus, E is the same for the same material, regardless of the length and cross sectional area, etc.
the SAME STEEL is used, so E is the same

26) ok now the molecules at Q are 2r from the source
and Intensity is inversely proportional to the distance from the source
d = 2r >> Intensity x 1/ 2^2 = 1/4
if intensity is decreasing by 4, and intensity is directly proportional to the amplitude...
then the amplitude is decreased by the square root of 4 = 2, so amplitude x 1/2
amplitude Q = 8 x 1/2 = 4 micrometers

 

[queen of the legend]

Use the formula, Force-Friction=mass * acceleration.
Force will be the the weight of the load that is pulling 8 kg load . now the F=2*9.81 =19.62 N
now Friction we are given which is 6.0 N.
now we are calculating the system's acceleration , so , the mass will be (8+2 ) =10 kg.
now ,
19.62 - 6 = 10 * acceleration
acceleration = 1.362
which is 1.4 m/s2

Can you please see this question that i have attached !

in this question originally the pressure = rho g h ....when hieght incresed by h again p= rho g 2h

 

[geek101]

Can you please see this question that i have attached !

when the pressure increases, the column on the right moves up by, h and the column on the right moves down by h.
so the total change in height is 2h
p = rho x g x delta h = rho g 2h

ps. a little shortcut, it says the pressure increases, therefore the formula has to be something that would give a higher value for the pressure, keeping in mind that the original pressure is rho g h
A and B wouldn't, C is like the original pressure, only D would =P