Physics: Post your doubts here!

[papajohn]

m = k/R
R = k/m

Increasing gradient will decrease R, so at maximum gradient, R will b minimum

Well if u see the graph, at B it is most steepest which means higher gradient than any other?The correct ans is C which against ur explaination

 

[Hadi Murtaza]

Well if u see the graph, at B it is most steepest which means higher gradient than any other?The correct ans is C which against ur explaination

I just gave da answer 2 wat u said, i didnt read da question

 

[Thought blocker]

Zaq Zainab Thought blocker & Suchal Riaz
I`m tagging u guys because the questions is very challenging and i only expect the right answer from you guys.
Here the is the question. My confusion is that why we take highest gradient point as the the lowest resistance where the resistance is the reciprocal.
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w05_qp_1.pdf
Q 34

I din't got your tag...
My way of doing this question:¬
Method i)
Make accurate scale diagram... Then at each point (A,B,C,D) calculate resistance with formula R = 1 / m you'll find at C there is lower resistance...
Method ii)
As R = V / I ; R is the ratio of V:I so when drawing a line of best fit i.e is drawing a st. line from origin (zero , zero) check which point is closer to the line, I got exact at C

Hope you got it..
Method i) would take sometime but will give accurate result if your scale is correct
Method ii) is also valid... I would prefer this method rather than first...
P.S. After completing whole paper, if I had a time, I would check it with both of this method.
All the best PAPA

 

[sagar65265]

Zaq Zainab Thought blocker & Suchal Riaz
I`m tagging u guys because the questions is very challenging and i only expect the right answer from you guys.
Here the is the question. My confusion is that why we take highest gradient point as the the lowest resistance where the resistance is the reciprocal.
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w05_qp_1.pdf
Q 34

The fact is that the gradient is not what affects the resistance; at any point, the resistance of a material can be obtained by applying a potential difference V across it's terminals, and measuring the current I through it. After doing this, the value of V/I should give you the resistance of the material. If they asked you at what point the rate of change of resistance was highest, then B makes complete sense.

However, since differentiation is all about minute changes (whole of calculus, really, but only differentiation is worth a look in this case) and we are concerned with exact values, we do not need differentiation to obtain an answer.

What Thought blocker has said above is absolutely right, which I think looks a little like this:

Hope this helped!

Good Luck for all your exams!

 

[papajohn]

Thanks pals!

 

[Thought blocker]

Thanks pal!

Welcome papa ji

 

[Thought blocker]

The fact is that the gradient is not what affects the resistance; at any point, the resistance of a material can be obtained by applying a potential difference V across it's terminals, and measuring the current I through it. After doing this, the value of V/I should give you the resistance of the material. If they asked you at what point the rate of change of resistance was highest, then B makes complete sense.

However, since differentiation is all about minute changes (whole of calculus, really, but only differentiation is worth a look in this case) and we are concerned with exact values, we do not need differentiation to obtain an answer.

What Thought blocker has said above is absolutely right, which I think looks a little like this:View attachment 44027

Hope this helped!

Good Luck for all your exams!

Well I din't get that differentiation part, explain me that thing differentiation q karna tha ?
And yes I meant the same thing

 

[sagar65265]

Well I din't get that differentiation part, explain me that thing differentiation q karna tha ?
And yes I meant the same thing

Just saying kyunki gradient of curve ek baar lena tha na, so gradient at A, B and C would be found by differentiation/ drawing gradient, etc. No need for it, just saying.

 

[Hadi Murtaza]

The fact is that the gradient is not what affects the resistance; at any point, the resistance of a material can be obtained by applying a potential difference V across it's terminals, and measuring the current I through it. After doing this, the value of V/I should give you the resistance of the material. If they asked you at what point the rate of change of resistance was highest, then B makes complete sense.

However, since differentiation is all about minute changes (whole of calculus, really, but only differentiation is worth a look in this case) and we are concerned with exact values, we do not need differentiation to obtain an answer.

What Thought blocker has said above is absolutely right, which I think looks a little like this:View attachment 44027

Hope this helped!

Good Luck for all your exams!

I disagree wid dis

 

[Thought blocker]

Just saying kyunki gradient of curve ek baar lena tha na, so gradient at A, B and C would be found by differentiation/ drawing gradient, etc. No need for it, just saying.

Oki oki

I disagree wid dis

LOL, Genius, batao q ?

 

[Hadi Murtaza]

Oki oki

LOL, Genius, batao q ?

Have u guys heard of tangent on curves ??

 

[Thought blocker]

Have u guys heard of tangent on curves ??

Going to bath.. I just did my treatment of whole body... Ake shamjha ta hu maine kya kiya... Ruko app...
Be back soon dear <3

 

[Hadi Murtaza]

Going to bath.. I just did my treatment of whole body... Ake shamjha ta hu maine kya kiya... Ruko app...
Be back soon dear <3

alrighty

 

[Thought blocker]

alrighty

So, lemme explain you...
R = V / I yes ?
It means R is in the ratio of V : I yes ?
And we are given I - V graph yes ?
So we can draw a line of best fit, that is from origin, and the line of best fit here is resistance.
And we are asked to find the least resistance in the whole graph..
We are given points A,B,C,D..
Now you attach all point from origin to A,B,C,D
you'll see The steepest line at C point... (Steepest the gradient lower will be the Resistance, hope you got the answer, if no lemme elaborate)
And as you know, R = 1/m yes ? ; so, High the m, less is the R : Here we have the steepest line at C then answer is C
Well, if we were asked for the highest resistance, answer would be A, as it has the lowest steepness from other three.
Hope you got it

 

[Hadi Murtaza]

So, lemme explain you...
R = V / I yes ?
It means R is in the ratio of V : I yes ?
And we are given I - V graph yes ?
So we can draw a line of best fit, that is from origin, and the line of best fit here is resistance.
And we are asked to find the least resistance in the whole graph..
We are given points A,B,C,D..
Now you attach all point from origin to A,B,C,D
you'll see The steepest line at C point... (Steepest the gradient lower will be the Resistance, hope you got the answer, if no lemme elaborate)
And as you know, R = 1/m yes ? ; so, High the m, less is the R : Here we have the steepest line at C then answer is C
Well, if we were asked for the highest resistance, answer would be D, as it has the lowest steepness from other three.
Hope you got it

U dont calculate gradient by joing a point wid origin -_-

 

[Thought blocker]

U dont calculate gradient by joing a point wid origin -_-

arey bhai... dekho...
Steepest line means it has highest gradient, which is when you join it to C point dear...
suno... maine yeh kaha hain.. ki high the m less is R, so high the steepness, less is R..
Hope now you get me
if not don't hesitate to ask

 

[Thought blocker]

U dont calculate gradient by joing a point wid origin -_-

Hadi, agar abhi bhi shamajh na aya ho na... meko inbox kardo kya shamajh nahi aya I'll explain there, yaha pe sab ko alerts mil rahi hogi . _ .

 

[Hadi Murtaza]

http://www.wolframalpha.com/input/?i=y+=+-(x-4)²+++10

arey bhai... dekho...
Steepest line means it has highest gradient, which is when you join it to C point dear...
suno... maine yeh kaha hain.. ki high the m less is R, so high the steepness, less is R..
Hope now you get me
if not don't hesitate to ask

Look at dis curve

 

[Hadi Murtaza]

http://www.wolframalpha.com/input/?i=y = -(x-4)² + 10

Look at dis curve

Wat is da gradient at da maximum point ?

 

[Thought blocker]

http://www.wolframalpha.com/input/?i=y = -(x-4)² + 10

Look at dis curve

Then ?