Physics: Post your doubts here!

[Mustehssun Iqbal]

Assalamu alaikum,
Q) In the circuit shown in Figure 10.35, what is the effective resistance between the points A and B??

 

[rz123]

Assalamu alaikum,
Q) In the circuit shown in Figure 10.35, what is the effective resistance between the points A and B??

1st of all lol at your drawing skills

is it 40 ooohms?
the ones in parallel might be calculated like this. 1/10 + 1/10= 1/R , and then 30 ohms in series i.e along the line from A to B point will be added. total 40. not sure.

 

[Mustehssun Iqbal]

1st of all lol at your drawing skills

is it 40 ooohms?
the ones in parallel might be calculated like this. 1/10 + 1/10= 1/R , and then 30 ohms in series i.e along the line from A to B point will be added. total 40. not sure.

hahaha at your comment on my drawing.
the book says it's 10 ohms.
It's from Pacific vol. 2, exercise 10.3, Q.8.
You couldn't do it. That means it's a challenging question. q:
thanks for trying though. : )

 

[rz123]

hahaha at your comment on my drawing.
the book says it's 10 ohms.
It's from Pacific vol. 2, exercise 10.3, Q.8.
You couldn't do it. That means it's a challenging question. q:
thanks for trying though. : )

maybe its like this. the current BYPASSES at the beginning travel upwards where a 10 ohm resistor is present. the resistor above is parallel with the resistor at the end of the line Ab. now the 10 ohm resistor at the end is also parallel to the 10 ohm resistor below as well. the lower loop i mean. so altogether it will be like 1/10+ 1/10 = 1/R and then again 1/10+1/10 =1/R. it will be 10 ohms. still not sure and confused about this one. need to go back towards book for the concept. ur welcome.

 

[Mustehssun Iqbal]

yeah that makes sense. Thanks!

 

[Mustehssun Iqbal]

Here's another question regarding DC circuits:
Calculate the resistance of the network shown below:
(a) between A and B;
(b) between A and C.
Editted:
Answers are 3 ohms and 4 ohms of a and b respectively.

 

[unique840]

Here's another question regarding DC circuits:
Calculate the resistance of the network shown below:
(a) between A and B;
(b) between A and C.
Editted:
Answers are 3 ohms and 4 ohms of a and b respectively.

A) between A and B: means current is entering at A and leaving at B. when this happens, the circuit is as shown. means the passage of current is either directly from A to B or from A-D-C-B. we will take both the passages in parallel. so the calculation for parallel resistance would be:
1/R = 1/12 + 1/4
R= 3 ohms

 

[unique840]

Here's another question regarding DC circuits:
Calculate the resistance of the network shown below:
(a) between A and B;
(b) between A and C.
Editted:
Answers are 3 ohms and 4 ohms of a and b respectively.

b) the current will enter at A and leave at C. it will either follow A-B-C or A-D-C. take both passages in parallel. it will be:
1/R = 1/8 + 1/8
R = 4 ohms

 

[rz123]

worksheet 15 , Question no. 14
worksheet 16 Question no. 12

marking scheme attached. kindly explain in a simple way and also mention the concepts applied. Thaaaaaaankyooooou!

 

[miss irfan]

heyyy, i want help in physics p5

 

[miss irfan]

if there is any direct link for p5 please post it, i am new to these forums

 

[Mustehssun Iqbal]

b) the current will enter at A and leave at C. it will either follow A-B-C or A-D-C. take both passages in parallel. it will be:
1/R = 1/8 + 1/8
R = 4 ohms

@Rvel Zahid
My school teacher told me this about the DC electricity question.
The redrawn circuit is like this.(uploaded)
The current doesn't flow from the R2 and flows from A to C to B and from A to D to B. Adding 20 ohms and 20 ohms in parallel results in 10 ohms.
The p.d. across the resistor R2 becomes zero. Ans is 10 ohms!

 

[Mustehssun Iqbal]

got more Phsyics p5s to practice with! OCR papers have planning questions.
http://www.xtremepapers.com/CIE/International A And AS Level/9702 - Physics/9702_s07_qp_5.pdf
marking scheme for OCR papers:
http://www.xtremepapers.com/OCR/Physics/2008 Jun/L_A_Level_Physics_A_MS_Jun_2008.pdf
what do you guys think??

 

[hassam]

wonderful.....http://www.xtremepapers.com/CIE/International A And AS Level/9702 - Physics/9702_s05_qp_4.pdf q6 part b???

 

[hassam]

http://www.xtremepapers.com/CIE/International A And AS Level/9702 - Physics/9702_s06_qp_4.pdf q6 c ..i have problem wid ms
what da hell has weight to do with vibration....

 

[Mustehssun Iqbal]

wonderful.....http://www.xtremepapers.com/CIE/International A And AS Level/9702 - Physics/9702_s05_qp_4.pdf q6 part b???

Assalamu alaikum,
I expect you have also done the first part of this question. You get E=deltaV/delta r or E= V/r or in other words, E is the gradient of V and r graph.
You can also sketch a graph on a rough paper , and as a rough work in exam which you can erase afterwards, by taking several values of r, or x which is the same thing in this case. The graph appears to be somewhat like this.(uploaded in the picture).
You get the idea of how the graph is sketched. The graph of E against r is steeper than the graph V against r axis. In the question, you draw a graph which is steeper and a little more downwards than the V against x graph.
Note: In the graph or E against r axis and V against r axis, in the uploaded picture, value of k comes out to be one.
You might find it better to confirm this answer. I don't pretend to be an expert on graphs though.

 

[Mustehssun Iqbal]

there's the diagram. q:

 

[Mustehssun Iqbal]

E = k/r^2 is another representation of E is inversely proportional to r^2.
V = k/r is similarly another representation of V is inversely proportional to r.
and there's one mistake in the diagram . It's corrected here. I wrote E = k/r instead of V = k/r. Apologies.
The correction is uploaded here.

 

[Mustehssun Iqbal]

wonderful.....http://www.xtremepapers.com/CIE/International A And AS Level/9702 - Physics/9702_s05_qp_4.pdf q6 part b???

And you might not need to draw the table along with the diagram each time this question comes. It's to get an idea of how the graph of E against r is sketched.

 

[hendrixgirl]

how do you find the are under the curves?
like in oct 07 question 5)b)ii)
where you have to find the charge?
i do not know how to find it. please help me out :s