Physics, Chemistry and Biology: Post your doubts here!

[GorgeousEyes]

I did that's the right answer. Was just wondering if pendulum would also work. Probably not since my answer's not in the mark scheme. Thanks

You are welcome

 

[Lightning soul]

and how to calculate paper 6 oct/nov 2009 question 1(ii) the t2/s2 question?

Just yout t/s squared so if t/s is 0.95 then t^2/s^2 = 0.95^2 = 0.9025
0.9025 to 3 significant figures is 0.903 which is the answer in the marking scheme

 

[Tim Diamond]

Please help papers.xtremepapers.com/CIE/Cambridge IGCSE/Physics (0625)/0625_s12_qp_61.pdf

Question 1 b)

 

[ZaqZainab]

http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Physics (0625)/0625_w10_qp_61.pdf

Q 1 C ,, I got a straight line in the graph so i can find the gradient by Y2-Y1/X2-X1 , but why in ms they say show a triangle ?

Q 1 D : what is the value of G ? and how ?

Q 3 C : whats the answer and explain please ?

+ Can I have a tip in choosing the scale of a graph when having decimals valus ?
Thanks in Advance !

this is called the triangle ans 3(c) you do 0.3*0.5=0.15
go to the table find where is 0.15 and its resistance is 10 ohms

 

[fatimanasir]

Just yout t/s squared so if t/s is 0.95 then t^2/s^2 = 0.95^2 = 0.9025
0.9025 to 3 significant figures is 0.903 which is the answer in the marking scheme

and how to calculate T/s ?

 

[fatimanasir]

ive got so many doubts how to plot values like 0.903 on graph?

 

[ZaqZainab]

ive got so many doubts how to plot values like 0.903 on graph?

this would be really close to 0.9 and it won't matter if it is slightly left or right because Ms has a +-0.1 you see!

 

[ZaqZainab]

http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Physics (0625)/0625_w08_qp_6.pdf
Question 2 i know how to place the voltmeter and ammeter but where in the world should i keep the resistor
how do i complete this?

 

[Lightning soul]

ive got so many doubts how to plot values like 0.903 on graph?

It's ok lets tackle these doubts one by one. T/s is a twentieth of t/s. You see, t/s is the time for 20 oscillations. T/s is the time for 1 oscillation. So just divide t/s by 20. Now to plot it, your graph must scale from 0.6 to 1 (range in which T^2 occurs) . There are 10 divisions. So you can make the bottom division 0.5 and the top division 1. Now each division represents 0.5. This makes it easier to plot 0.903 if you cannot plot it just try to plot the point closest to it.

 

[fatimanasir]

It's ok lets tackle these doubts one by one. T/s is a twentieth of t/s. You see, t/s is the time for 20 oscillations. T/s is the time for 1 oscillation. So just divide t/s by 20. Now to plot it, your graph must scale from 0.6 to 1 (range in which T^2 occurs) . There are 10 divisions. So you can make the bottom division 0.5 and the top division 1. Now each division represents 0.5. This makes it easier to plot 0.903 if you cannot plot it just try to plot the point closest to it.

this would be really close to 0.9 and it won't matter if it is slightly left or right because Ms has a +-0.1 you see!

Thanks

 

[Lightning soul]

http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Physics (0625)/0625_w08_qp_6.pdf
Question 2 i know how to place the voltmeter and ammeter but where in the world should i keep the resistor
how do i complete this?

One resistor is on AB the other is on CD. These resistors represent the resistance of the wires AB and CD. When drawing circuit diagrams the wires in them are assumed to be perfect conductors. The wires AB and CD have a certain resistance that's why on the circuit diagram you represent that resistance with resistors

 

[ZaqZainab]

One resistor is on AB the other is on CD. These resistors represent the resistance of the wires AB and CD. When drawing circuit diagrams the wires in them are assumed to be perfect conductors. The wires AB and CD have a certain resistance that's why on the circuit diagram you represent that resistance with resistors

what about S is it connected to the resistor? And thanks

 

[Jelleh Belleh]

Hi everyone. If they don't specify, should we join points on graph using ruler or free hand?

 

[ZaqZainab]

Hi everyone. If they don't specify, should we join points on graph using ruler or free hand?

ruler if they don't mention

 

[Lightning soul]

what about S is it connected to the resistor? And thanks

Np When S is connected it'll be after the resistor. You want to know the potential before the resistor and the potential after. Although I'm not so sure about the voltmeter. Here's what the examiners report says "Many candidates found it difficult to score full marks here. Most candidates knew the circuit symbols but did not score the mark for a correct arrangement. It seemed that many had been trained using past papers and assumed, without proper consideration, that this would be the same as previous circuits they had seen. Therefore, many connected the voltmeter across the power source."

 

[Lightning soul]

ruler if they don't mention

Unless it's an obvious curve (typically for temperature). Then you cannot use a ruler.

 

[Ahmed Al Hilali]

this is called the triangle ans 3(c) you do 0.3*0.5=0.15
go to the table find where is 0.15 and its resistance is 10 ohms

couldnt get 3 C

 

[ZaqZainab]

can i do a graph like this 40,50,60 .... without adding 0,10,20,30???
actually the graph should be 0,10,20,30,40 but it won't fit so what do i do if i take 0,20 that makes the graph not fit more than the half as they say it should be more what should i do?

 

[taffycandy]

q1(b) The mass is cylindrical and has a diameter slightly larger than the width of the metre rule.
Describe briefly how you would place the mass so that its centre of mass is exactly over
the 90.0 cm mark on the metre rule. You should draw a diagram and mark the position of
the centre of mass on the cylinder(0625_s12_qp_61.pdf)
pllzzzz help me immediately wd dis plzzplzzz

 

[Lightning soul]

can i do a graph like this 40,50,60 .... without adding 0,10,20,30???
actually the graph should be 0,10,20,30,40 but it won't fit so what do i do if i take 0,20 that makes the graph not fit more than the half as they say it should be more what should i do?

That's exactly what you're supposed to do. If suppose a graph has 5 divisions and the values range from 50 to 100. Then you start with 50 instead of 0