Biology; Chemistry; Physics: Post your doubts here!

[princess Anu]

Ohh

 

[DaniyalK]

http://papers.xtremepapers.com/CIE/Cambridge International O Level/Physics (5054)/5054_w12_qp_21.pdf
q2 a ii??

plzz help

From the table, a temperature difference of 50C produces a voltage increase of 1.5V. A temperature difference of x will produce a voltage difference of 0.6V (6.8-6.2).
50: 1.5
x : 0.6
Cross multiply and solve. x = 20. So there will be temp. rise of 20C. Add that to the original temperature. 750 + 20 = 770C

 

[mohammad ahmed]

From the table, a temperature difference of 50C produces a voltage increase of 1.5V. A temperature difference of x will produce a voltage difference of 0.6V (6.8-6.2).
50: 1.5
x : 0.6
Cross multiply and solve. x = 20. So there will be temp. rise of 20C. Add that to the original temperature. 750 + 20 = 770C

thnaks

 

[princess Anu]

Q10 a (III)
http://papers.xtremepapers.com/CIE/Cambridge International O Level/Physics (5054)/5054_w10_qp_22.pdf

 

[kirann]

how to do part a??

 

[DaniyalK]

how to do part a??View attachment 43044

2.8 : 2
x : 10

 

[kirann]

2.8 : 2
x : 10

i cant get it

 

[FLRNAB]

I don't know if it was only me or not.But I had been given no info abt centripetal force whtsoever except tht it,s perpendicular and all tht.I hooked it up on the internet and must say tht I have grasped tht concept fully.Needless to sya,A more detailed study abt this force shud have been include in our syllabus.
Ok then I,ll tell.
The cntrp force is always towards the centre of circle when CONSTANT motion..The resultant force at tht instant is towards the centre,i.e B and will change in direction retaining dir towards the centre of the circle as the car travles along the circle.At tht instant the resultant force towards B coupled with the speed of the car(which is a must,the car need not exert a force but initially shud have speed) causes it to move in the prejoctory of C but the problem is tht the centripetal force changes in dirction as the car travels a bit forward and thus keeps on changing its dirction ultimately travelling in a circle.One of the most imp part of question is CONSTANT speed which means no other force frm car is applied and resultant wud be B.If u r still wondering tht shudn,t the car be travelling in B direction then remember the initial speed and the fact tht this centrp force is instantaneous and changing continuously so in tht instant the resultan force is B.
visit physicsclassroom site,it,s awesome
Abt ur lens question..Of course we wud know how much it bends coz the pts wud focus at tht pt on the screen originally found by passing thru centre.
Ur,s is correct but not on the context tht the line wud be parallel to P axis ..I mean it,s only parallel when it passes thru FOCAL POINT and then meets the lens.Do u know ehre the focal pt of the lens is?(in tht question)
Like I said ,it,s correct on the pretext tht ray frm top of image despite hitting anywhere on lens will meet the point originally found by the line passing thru centre

Yes as it says that they meet on the film so that is the focal point. Tell me which ray is correct? They all converge at one point.

 

[mohammad ahmed]

anybody can tell me which diagrams shall tyhey ask to draw in paper??
i mean like dc motor etc??

 

[princess Anu]

http://papers.xtremepapers.com/CIE/Cambridge International O Level/Physics (5054)/5054_w04_qp_2.pdf

Q9 b (iv)

 

[DaniyalK]

i cant get it

It says the 2 quantities are proportional. So you use the ratio method.

 

[funky brat]

Can someone answer these doubts:

- What do we need to know about the Expansion of solids, liquids, gases topic?
- What are Capacitors? And what is a time delay circuit?
- Centripetal force? I can't find that anywhere in the book. =.=
- What are the ways of preventing heat loss in Homes?
- Do we need to know about Photocopies, Van De graff generators? How much is required?
- Can i skip Electronic systems? Is that a good idea?
- Do questions in Physics paper 2 repeat? What would be better, to read marking schemes, or to read the book?
- What is Linearity in a thermometer?
- And how to increase sensitivity. I know that it can be increased by decreasing the size of bore, but i also read somewhere it can be increased by increasing the volume of liquid in bulb? How does that work?
- Why should a switch and fuse be placed on the live wire?
- Diodes? What do we need to know about them?

I'm confused about this too, in the book it says the bulb needs to be small to contain less liquid which makes the thermometer responsive.

 

[funky brat]

Can somebody explain with the aid of a diagram how total internal reflection occurs in Optical fibres, with clear angle of incidence etc.

 

[Faizan Muhammmad]

I'm confused about this too, in the book it says the bulb needs to be small to contain less liquid which makes the thermometer responsive.

it is more responsive because less volume means that all the mercury is heated quickly

 

[Dark Destination]

it is more responsive because less volume means that all the mercury is heated quickly

Yes, but More volume = Sensitive?

 

[DaniyalK]

http://papers.xtremepapers.com/CIE/Cambridge International O Level/Physics (5054)/5054_w04_qp_2.pdf

Q9 b (iv)

something like this.

 

[funky brat]

it is more responsive because less volume means that all the mercury is heated quickly

Yeah but that's sensitive too, how?

 

[Dark Destination]

are old p1's more tough or new?

 

[kirann]

is it really necessary to use H OR HB pencil for mcq's i mean cant we use 2HB, cause i used it in biology p1

 

[Dark Destination]

is it really necessary to use H OR HB pencil for mcq's i mean cant we use 2HB, cause i used it in biology p1

I didn't even see which pencil it was