Physics: Post your doubts here!

[NinjaInPyjamas]

http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s08_qp_2.pdf

can someone help question 6 b please!

 

[mehria]

Thanks

u're welcum

 

[Thought blocker]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s08_qp_2.pdf

can someone help question 6 b please!

Thanks to ZaqZainab

when S2 is closed the "path of least resistance" will take up most of the current
so the current would flow through S2 rather than through B cause here B has resistance
for (i) we use power= VI
we don't have I so we replace I with V/R which we take from the equation R=V/I
power=v^2/r
R=38.4
ii) they are talking about total poser
so if S1 open there is no power you get this one right because the circuit is not complete
S1 and S2 closed as i said current always takes easier path so it will not go through B so in P=IV I=O the P is also 0 for B but then the current flows through A so its 1.5k+0=1.5k
if all of them are closed here again we will take power of B as 0 and if you see we have A and C in parallel Total power=P1+P2......... SO 1.5+1.5
S1 is closed so so we have A and B in series 1/total power = 1/p1 + 1/p2 +............
so 1/total power= 1/1.5 +1/1.5
total power =0.75
here s1 and S3 are closed so we have A and B parallel to C ie (AB) parallel to C for parallel Total power=P1+P2.........
and we already found AB which is 0.75 so now we just need to add 1.5

 

[NinjaInPyjamas]

Thanks to ZaqZainab

when S2 is closed the "path of least resistance" will take up most of the current
so the current would flow through S2 rather than through B cause here B has resistance
for (i) we use power= VI
we don't have I so we replace I with V/R which we take from the equation R=V/I
power=v^2/r
R=38.4
ii) they are talking about total poser
so if S1 open there is no power you get this one right because the circuit is not complete
S1 and S2 closed as i said current always takes easier path so it will not go through B so in P=IV I=O the P is also 0 for B but then the current flows through A so its 1.5k+0=1.5k
if all of them are closed here again we will take power of B as 0 and if you see we have A and C in parallel Total power=P1+P2......... SO 1.5+1.5
S1 is closed so so we have A and B in series 1/total power = 1/p1 + 1/p2 +............
so 1/total power= 1/1.5 +1/1.5
total power =0.75
here s1 and S3 are closed so we have A and B parallel to C ie (AB) parallel to C for parallel Total power=P1+P2.........
and we already found AB which is 0.75 so now we just need to add 1.5

thank you so much!

 

[Thought blocker]

unique111
Potentiometers are variable resistors. Potentiometers are resistors where the resistance can be changed using a knob or a slider. Potentiometers are used to control many things, including how bright or dim the lights in your house are and the volume controls on your television.

There are many different types of potentiometers. These different types include carbon potentiometers, plastic potentiometers, and wire potentiometers. Carbon potentiometers are the most common potentiometers that we use today because they are inexpensive to make and are easy to put together. Wire potentiometers are the most powerful type out of the three listed above. The wire inside the potentiometer is wound so that it has more power. Plastic potentiometers have the same amount of power that carbon potentiometers do, but are of a higher quality. They are made of a special kind of plastic that conducts electricity just as effectively as carbon potentiometers. It as a better life than carbon potentiometers do. Trimmer potentiometers are small.

If more help : http://www.wikihow.com/Wire-a-Potentiometer

Detailed notes : http://web.cecs.pdx.edu/~eas199/A/topics/circuits/pot_voltage_divider.pdf

 

[Anzuman turin]

can anyone help me out with explanations ?

 

[mehria]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s08_qp_2.pdf

can someone help question 6 b please!

Thought blocker's explanation is correct but the proportionality of P to V2 wasn't mentioned so to just highlight that i still intended to post this ....

 

[Thought blocker]

Thought blocker's explanation is correct but the proportionality of P to V2 wasn't mentioned so to just highlight that i still intended to post this ....

Np

 

[mehria]

Np

 

[Thought blocker]

can anyone help me out with explanations ?
View attachment 38531
View attachment 38529 View attachment 38530 View attachment 38532

I am online from tab, and it will take a lot time to reply, and I have to finish M1 so please help her asap
ZaqZainab
midha.ch
Suchal Riaz
sagar65265

 

[ZaqZainab]

can anyone help me out with explanations ?
View attachment 38531
View attachment 38529 View attachment 38530 View attachment 38532

17 would be A cause if you complete the lines of the force acting all should intersect at the same point

24 you are given the spring constant the firmula for spring constant is K=F/e
where K is the spring constant F is the force and e is the extension
as the trolley is that rest the force applied by P = force by Q
Force by P=k*e=60*0.40=24
Force by Q=k*e=120*e=24
e=24/120=0.2
15. the viscous force in the starting is 0 and it keeps increasing until the body comes to rest so the answer is not A
The upthrust would stays the same

 

[ZaqZainab]

Thanks to ZaqZainab

when S2 is closed the "path of least resistance" will take up most of the current
so the current would flow through S2 rather than through B cause here B has resistance
for (i) we use power= VI
we don't have I so we replace I with V/R which we take from the equation R=V/I
power=v^2/r
R=38.4
ii) they are talking about total poser
so if S1 open there is no power you get this one right because the circuit is not complete
S1 and S2 closed as i said current always takes easier path so it will not go through B so in P=IV I=O the P is also 0 for B but then the current flows through A so its 1.5k+0=1.5k
if all of them are closed here again we will take power of B as 0 and if you see we have A and C in parallel Total power=P1+P2......... SO 1.5+1.5
S1 is closed so so we have A and B in series 1/total power = 1/p1 + 1/p2 +............
so 1/total power= 1/1.5 +1/1.5
total power =0.75
here s1 and S3 are closed so we have A and B parallel to C ie (AB) parallel to C for parallel Total power=P1+P2.........
and we already found AB which is 0.75 so now we just need to add 1.5

Feels honored

 

[Thought blocker]

17 would be A cause if you complete the lines of the force acting all should intersect at the same point
View attachment 38547
24 you are given the spring constant the firmula for spring constant is K=F/e
where K is the spring constant F is the force and e is the extension
as the trolley is that rest the force applied by P = force by Q
Force by P=k*e=60*0.40=24
Force by Q=k*e=120*e=24
e=24/120=0.2
15. the viscous force in the starting is 0 and it keeps increasing until the body comes to rest so the answer is not A
The upthrust would stays the same

Genius

 

[ZaqZainab]

Anzuman turin
this isnt perfectly drawn but yeah it would be something like this

 

[Anzuman turin]

Anzuman turin View attachment 38549
this isnt perfectly drawn but yeah it would be something like this

thanks a lot help me can you please help me with other questions?

 

[Anzuman turin]

.

 

[yesow747]

can any one give me a link to AL Physics CIE revision notes , which contain revision for applications of physics ?? thank you very much

 

[Thought blocker]

 

[ZaqZainab]

thanks a lot help me can you please help me with other questions?

1 loop -f
2 loop will be -2f
you cross multiply

 

[ZaqZainab]

R is proportional to L
and R is inversely proportional to A
A wire has resistance R it is rolled out so the LENGTH is DOUBLED but volume stays same
as the volume is same that mean they just not take another cylindrical wire and add to the cylindrical piece they ROLLED this one that mean the AREA is Decreasing have you ever played with play dough? if you have you would have see when you keep rolling it it becomes thinner and thinner
So now we know the Area decreases and the Length increases
and again
R is proportional to L so more the L more the R and vise versa
and R is inversely proportional to A so more the A less the R and vise versa
here L increases by *2 so does the R so R becomes 2R
the A decreases by 1/2 so the 2R should increase by *2 it become 4R