Physics: Post your doubts here!

[Ahmed Aqdam]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w04_qp_2.pdf
Q1 b part 2 uncertainty never understood it can u explain clearly how to do

As area's formula: pi x r^2, the percentage uncertainty is doubled when squared so 8%.

 

[IGCSE13]

Y

The loop does not pass through BJ so I2 isn't included.

Thanks

 

[_Ahmad]

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_s10_qp_21.pdf

Q5 b ii)
Can anyone please tell which region is C and D with explanation.

 

[IGCSE13]

because the loop HBCDJFGH doesn't include BJ so we will not include I2R2/2

Thanks

 

[omaaaar]

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_s11_qp_21.pdf
Q1 b part complete

 

[Suchal Riaz]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s10_qp_21.pdf

Q5 b ii)
Can anyone please tell which region is C and D with explanation.

in this diagram the seperation of lines represent how weak the strength is. when the lines are almost parallel as well as the distance is same they are uniform. so by diagram they are uniform at centre of rod.
and decreasing means the lines are spreading aways(their distance increase).

 

[Mohammed salik]

Any One?

Some One Plz DRAW THEM Plz..!
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s11_qp_23.pdf Q6 C )iv)


http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w13_qp_21.pdf Q5)b)

Thnx In ADVANCE..!

 

[AhsanAfzal]

for definition emf should we write work done in driving a unit charge around a circuit or should we write chemical energy converted to electrical energy per unit charge?

 

[Suchal Riaz]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s11_qp_21.pdf
Q1 b part complete

resistivity = R A/L = 7.5* pi r² / 1.75 m = 7.5* pi (0.38 e -3 /2)² / 1.75 m = 4.86e-7

in this curly d(somthing)/something = percentage uncertainty
so dp/p = 3/1750 + 2*0.01/0.38+0.2/7.5 * 100= 8.13%
dp = 8.13% * 4.86e-7 = 0.395e-7

in this e is shortcut for writing X10^

 

[Suchal Riaz]

for definition emf should we write work done in driving a unit charge around a circuit or should we write chemical energy converted to electrical energy per unit charge?

it depends on the marks though. i have only seen energy converted into electric form of energy when in columb of charge passes through complete loop in markschemes

 

[TheJDOG]

for definition emf should we write work done in driving a unit charge around a circuit or should we write chemical energy converted to electrical energy per unit charge?

Second one

 

[Suchal Riaz]

Any One?

after 1/4 T the wave will be a straight line. to see why the antinodes go back to their original position(complete one oscilation in one T) so in 1/4th they complete 1/4th of their oscillation. which is from max to zero, then from zero to min, then from min to zero then from zero to max.

 

[Mohammed salik]

after 1/4 T the wave will be a straight line. to see why the antinodes go back to their original position(complete one oscilation in one T) so in 1/4th they complete 1/4th of their oscillation. which is from max to zero, then from zero to min, then from min to zero then from zero to max.

How would we draw that onto The Exam paper?

 

[Suchal Riaz]

How would we draw that onto The Exam paper?

draw a straight line
like this:

 

[Mohammed salik]

draw a straight line
like this:

In Both of them?

 

[Mohammed salik]

Because Some People Suggested This https://www.xtremepapers.com/community/attachments/untitled-png.42529/ ?????
Is This Right?

 

[Suchal Riaz]

 

[Mohammed salik]

View attachment 42553

Whats The diffrence Between two Question?
Why did u Draw like this For http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w13_qp_21.pdf
But Diferrent for Other One?

 

[MiniSacBall]

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_s10_qp_22.pdf

Q4 c)

Why λ/4, why not λ/6 or λ/8...etc.
Explain please?

 

[Suchal Riaz]

Whats The diffrence Between two Question?
Why did u Draw like this For http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w13_qp_21.pdf
But Diferrent for Other One?

the first one is stationary and second one is progressive