Physics: Post your doubts here!

[johnjase0]

can anyone send me a level full physics revision notes and worksheet plzzzzzzz
i need it plzz some one help me if you have it send it to [email protected] and if you need any other help in AICT and maths i will help you
but plzzz send me notes guys

 

[Suchal Riaz]

Anyone please tell me which books are best for physics and why they are best.

 

[Jaspreet Dhaliwal]

can someone please help me with this question, the answer is B by the way

 

[salvatore]

http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_w05_qp_4.pdf
Could anyone please help me with qn no. 1 (b)? I don't understand what the marking scheme has d0ne..
Thanks

 

[adibshamsuddin]

E =-V/D .Why the minus sign?? book says V increases towards the right and F is in the opposite direction. What they do mean by V increases towards the right???

 

[snowbrood]

E =-V/D .Why the minus sign?? book says V increases towards the right and F is in the opposite direction. What they do mean by V increases towards the right???

The force on the charge is F = qE where E is the field pushing the charge q. So the work done on the charge is just Q = Fd = qEd = q(V/d)d = qV; where E = V/d is the field between the two plates with voltage V and distance d.
note if the object moves in the direction of applied force the work done is positive however if the object movers in opposite direction then work done is negative in this case force is from positive to negative plate while the electron moves from negative to positive

 

[snowbrood]

can someone please help me with this question, the answer is B by the way

u dont need to know useless formulas u might know that mass=volume*density
we need to find the volume of the wall
volume=area*distance
distance=velocity*time
mass=2000*10*t*1.3
F=MV/T
F =(2000*10*t*1.3*10)/t=260kN
P=fv =260*10=2600K
since conversion is 50% 2600/2=1300K

 

[adibshamsuddin]

How do I solve question C? Between A and B field strength is 2kv/0.25=8kv. Now for C and D is it also the same. I mean is electric field strength same at all points (whatever their position is) in an uniform field?? I know I sound like a dumbo but doesn't electric field strength decrease with increasing d. Here C is at the midpoint of A and B and D is at midpoint of C and B, so how is it possible?

 

[Jaspreet Dhaliwal]

u dont need to know useless formulas u might know that mass=volume*density
we need to find the volume of the wall
volume=area*distance
distance=velocity*time
mass=2000*10*t*1.3
F=MV/T
F =(2000*10*t*1.3*10)/t=260kN
P=fv =260*10=2600K
since conversion is 50% 2600/2=1300K

that wasnt the answer sorry hahah

 

[Jinosupreme]

How do I solve question C? Between A and B field strength is 2kv/0.25=8kv. Now for C and D is it also the same. I mean is electric field strength same at all points (whatever their position is) in an uniform field?? I know I sound like a dumbo but doesn't electric field strength decrease with increasing d. Here C is at the midpoint of A and B and D is at midpoint of C and B, so how is it possible?

Yes, the electric field strength is constant at any point. The thing that change is the voltage across, acceleration of the particles/sub-particles , they will be different at different position, but NOT the electric field strength

 

[Jinosupreme]

http://papers.xtremepapers.com/CIE/...d AS Level/Chemistry (9701)/9701_s03_qp_1.pdf

Guys I need help :0,
Q40 m what is K-capture??

 

[Jinosupreme]

http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s04_qp_1.pdf

Need help in question 14, 25, 26
14B
25A
26B

Thanks a lot!!!

 

[snowbrood]

u dont need to know useless formulas u might know that mass=volume*density
we need to find the volume of the wall
volume=area*distance
distance=velocity*time
mass=2000*10*t*1.3
F=MV/T
F =(2000*10*t*1.3*10)/t=260kN
P=fv =260*10=2600K
since conversion is 50% 2600/2=1300K

edit
p=E/T=0.5*mv^2/t=0.5*(2000*10*t*1.3810)*10^2/t=1300k
since conversion is 50% so 650K Watts i dont get why the first method didnt work i will consult my teacher

 

[snowbrood]

edit
p=E/T=0.5*mv^2/t=0.5*(2000*10*t*1.3810)*10^2/t=1300k
since conversion is 50% so 650K Watts i dont get why the first method didnt work i will consult my teacher

that wasnt the answer sorry hahah

oh yes i found my mistake we will have to find average force that is we divide 260 by 2. i falsely assumed that final velocity of wind will be zero my bad

 

[farhan141]

Anyone please tell me which books are best for physics and why they are best.

Yo bro. I heard Pacific A Level Physics Vol 1 and 2 (Poh) and Physics A-Level (David Sang, Graham Jones) are good for now.

For Chemistry I got the Chemistry AS and A Level Coursebook by Roger Norris.

 

[Navjot Singh]

Hey Guys
i have a doubt ...
9702_s05_qp_1 ..
question 20 .
I need help ASAP

 

[Navjot Singh]

Hey Guys
i have a doubt ...
9702_s05_qp_1 ..
question 20 .
I need help ASAP

 

[adibshamsuddin]

I have a question about polarization. My question is if the Polaroid is aligned vertically will vertically polarized light will pass through or horizontally polarized light will pass through? vertically aligned means it will stop vertically polarized light or does it mean it will stop all other polarized lights and allow vertically polarized light to pass through..real confused here

 

[KZW]

I have a question about polarization. My question is if the Polaroid is aligned vertically will vertically polarized light will pass through or horizontally polarized light will pass through? vertically aligned means it will stop vertically polarized light or does it mean it will stop all other polarized lights and allow vertically polarized light to pass through..real confused here

It will stop vertically polarized light.

 

[Jaspreet Dhaliwal]

GUYS GOT MOCKS TOMMOROW HELP PLEAAASE!!
http://olevel.sourceforge.net/papers/9702/9702_s13_qp_12.pdf

QUESTION 9
QUESTION 14
QUESTION 17
QUESTION 23
QUESTION 24
QUESTION 27
QUESTION 29
QUESTION 37

PLEASE HELP GUYS!