Physics, Chemistry and Biology: Post your doubts here!

[Mai(M4!)]

This is in the syllabus "perform and describe an experiment (involving vertical forces) to show that there is no net moment on a body in equilibrium"
Could you tell me what is this experiment?

 

[sj0007]

This is in the syllabus "perform and describe an experiment (involving vertical forces) to show that there is no net moment on a body in equilibrium"
Could you tell me what is this experiment?

The experiment could be something like this:
A bar of 1 metre with a pivot at the 0.5m mark
Take two forces at different distances at either side of the pivot and make sure that the clockwise moment is equal to the anticlockwise moment
Hope this is useful

 

[Hibaaa]

Hello i needed help in this question... plsss...
Suggest and explain how a named insect could evolve over a period of time. (0610_s03_qp_3.pdf)

Let me try and explain this..
1st of all it says "named" so u have to name an insect. For example grasshoper or locust
then say how it evolves so ideally the answer should be like:
The grasshopper had developed a mutation. This mutation caused variation. This mutation behaved like a selective advantage feature and it survived competion and predetors and continued to live. Selection Pressures caused it to reproduce with other grasshoppers which survived and were not killed so it reproduced and passed its genes to the next generation and this is how a new species of grasshoppers evolved.
OOOH AND ALSO IF U MENTION THE MUTATION LIKE FOR EXAMPLE STRIPPED THORAX OR SOMTHING THEN U WOULD GET MORE MARKS.
THIS ANSWER THOUGH WOULD PROBS BE ENOUGH TO GET YOU FULL MARKS FOR QUESTION.

 

[Saad the Paki]

Help pliz.. In q 4 (b)(i) & (ii)....
http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Physics (0625)/0625_s10_qp_31.pdf
Apparently when the black bulb emits radiation so air EXPANDS and pressure INCREASES.. However i thought that increase in volume would decrease pressure will increase (Boyle's Law).. :/

 

[Barkha Sharma]

hello everybody is there anyone who is appearing for physics chemistry and biology (0625,0620,0610) practicals in the march series (which is only for India)??

 

[masterex567]

Help pliz.. In q 4 (b)(i) & (ii)....
http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Physics (0625)/0625_s10_qp_31.pdf
Apparently when the black bulb emits radiation so air EXPANDS and pressure INCREASES.. However i thought that increase in volume would decrease pressure will increase (Boyle's Law).. :/

In a U-tube manometer, there is a different scenario. Since the air expands, it exerts more pressure on the left hand side of the manometer.
Hence it PUSHES the water down on left causing it to move up on the right.

Don't relate things being proportional or inversely proportional in physics automatically since its not always a set rule, you have to understand and then relate.
Cheers.

 

[Saad the Paki]

In a U-tube manometer, there is a different scenario. Since the air expands, it exerts more pressure on the left hand side of the manometer.
Hence it PUSHES the water down on left causing it to move up on the right.

Don't relate things being proportional or inversely proportional in physics automatically since its not always a set rule, you have to understand and then relate.
Cheers.

OMG.. Thanks you sooooo much..!

 

[sfhn_128]

I heard that the last ques in p-6 is not there....IS THAT TRUE????
Plz help ASAP!!

 

[sj0007]

In chemistry p-6, is the last experiment ques in syllabus 2015??

I didnt't get ur question............

 

[Saad the Paki]

Hey .. someone help me out with this..
So in paper 6 (Alternative to practical) for physics and chemistry..
If the question says draw a smooth curve.. should the curve pass through ALL the points (excluding the incorrect point) or is it like a best fit curve?

 

[Atharva Joshi]

Hey .. someone help me out with this..
So in paper 6 (Alternative to practical) for physics and chemistry..
If the question says draw a smooth curve.. should the curve pass through ALL the points (excluding the incorrect point) or is it like a best fit curve?

I guess the curve is more like a best fit curve.

 

[NOneed2speedd]

Please some one help me with this problem. .. i have exam tomorrow
On the following question answer in mark scheme is 9.5.. but mine is coming exact 9

 

[NOneed2speedd]

And in this question answer on ms is v=4.4 and u=2.6

But mine is coming v= 4cm and u 2.4 cm

 

[My Name]

Please some one help me with this problem. .. i have exam tomorrow
On the following question answer in mark scheme is 9.5.. but mine is coming exact 9

And in this question answer on ms is v=4.4 and u=2.6

But mine is coming v= 4cm and u 2.4 cm

Those are paper 6 questions, right?
Don't worry for your real exam you will get an original paper so your measurements will be exact!
That used to happen to me as well (answers weren't what the mark scheme had to say).

I'd say your values are close enough.

 

[NOneed2speedd]

Those are paper 6 questions, right?
Don't worry for your real exam you will get an original paper so your measurements will be exact!
That used to happen to me as well (answers weren't what the mark scheme had to say).

I'd say your values are close enough.

Yes it's p6... thanks vry mch

 

[My Name]

Yes it's p6... thanks vry mch

Welcome

 

[Saad the Paki]

Can someone please help me out on this.!
Q6 a) i) and ii)... can u please explain with reasons.! Thanks in advance.!

 

[sj0007]

Can anyone tell me how to draw the reflection of circular wavefronts? like in question 10 of the paper: w10 qp 33
Thnx.................

 

[sj0007]

Can anyone tell me how to draw the reflection of circular wavefronts? like in question 10 of the paper: w10 qp 33
Thnx.................

 

[masterex567]

Can someone please help me out on this.!
Q6 a) i) and ii)... can u please explain with reasons.! Thanks in advance.!

Q6 a) i) is Range.
Range is the difference between highest and lowest temperature,
now if you increase the stem of the thermometer you'll have a larger difference between highest and lowest hence a bigger range.

Q6 a) ii) is Sensitivity.
Sensitivity is how much the liquid expands per rise in temperature.
If you want it to react more per temperature rise, decreasing diameter of the capillary tube to make it thin, will make the liquid rise up more according to scale.
Hence if diameter reduced, liquid will seem to expand more per degree rise.