Physics, Chemistry and Biology: Post your doubts here!

[GorgeousEyes]

could u click on it again ?

It says the file is damaged and could not be opened.

 

[Iridescent]

could u click on it again ?

Firstly, when I click the link, I don't get the paper and only the site opens. It's written 'Internal server error' on top. When I download the paper, it says that it is damaged.

 

[GorgeousEyes]

91 paper

 

[GorgeousEyes]

Firstly, when I click the link, I don't get the paper and only the site opens. It's written 'Internal server error' on top. When I download the paper, it says that it is damaged.

No problem i am gonna upload the pictures incha'allah .

 

[Iridescent]

91 paper

1. The answer is A because heating makes the iron bar expands, increasing its length. So, the roller will slightly move in the clockwise direction and thepointer will move towards the right.
2. The answer is A because metal is a conductor. Any electrons gained or lost during rubbing will be replaced by the earth. Other all are insulators and will retain the charge.
3. There was a two-day time given between Monday and Wednesday. B is the sample that decreased to half of its original value in that time i.e., from 200 to 100. A and D decreased by 4 times while C remained unchanged so they all are wrong.
4. The answer is B because the image formed on a plane mirror has to be laterally inverted, not upside down.
5. It is a cooling curve, not a heating curve. Thus, it is solidification, where no temperature change is taking place. After completely solidifying, the temperature of the solid is decreasing.
6. Same as the first question.
7. Same as the third question.
8. The answer is D because more number of coils are present so more magnetic field lines are being cut which increases the force on the coil and thus it rotates faster.
9. Same as the fourth question.
10. Same as the fifth question.

 

[GorgeousEyes]

1. The answer is A because heating makes the iron bar expands, increasing its length. So, the roller will slightly move in the clockwise direction and thepointer will move towards the right.
2. The answer is A because metal is a conductor. Any electrons gained or lost during rubbing will be replaced by the earth. Other all are insulators and will retain the charge.
3. There was a two-day time given between Monday and Wednesday. B is the sample that decreased to half of its original value in that time i.e., from 200 to 100. A and D decreased by 4 times while C remained unchanged so they all are wrong.
4. The answer is B because the image formed on a plane mirror has to be laterally inverted, not upside down.
5. It is a cooling curve, not a heating curve. Thus, it is solidification, where no temperature change is taking place. After completely solidifying, the temperature of the solid is decreasing.
6. Same as the first question.
7. Same as the third question.
8. The answer is D because more number of coils are present so more magnetic field lines are being cut which increases the force on the coil and thus it rotates faster.
9. Same as the fourth question.
10. Same as the fifth question.

Thank youuu for your greaat help !

 

[GorgeousEyes]

Paper 94
.. 1st one why did we say above atmospheric pressure?
2nd one .. When distance increase force decrease but work done increase . I am i right?
http://www.freeexampapers.com/#IGCSE/Physics/CIE/1995 Jun <== june 95
please no.12 ,32,31,21
http://www.freeexampapers.com/#IGCSE/Physics/CIE/1995 Nov
no.33 , no.31
http://www.freeexampapers.com/#IGCSE/Physics/CIE/1996 Jun
no.11 ,14

 

[GorgeousEyes]

Paper 94
.. 1st one why did we say above atmospheric pressure?
2nd one .. When distance increase force decrease but work done increase . I am i right?
http://www.freeexampapers.com/#IGCSE/Physics/CIE/1995 Jun <== june 95
please no.12 ,32,31,21
http://www.freeexampapers.com/#IGCSE/Physics/CIE/1995 Nov
no.33 , no.31
http://www.freeexampapers.com/#IGCSE/Physics/CIE/1996 Jun
no.11 ,14

Anyone ?

 

[sourov97]

Paper 94
.. 1st one why did we say above atmospheric pressure?

if u hold the u tube with the mercury only (no gas connected), then u will see that the height on both of the columns will be same....this is because the atmosphere is giving pressure on both open end of the tube which are equal in size. now if u connect a gas supply to one end and the other is left open (atmosphere is still giving a pressure)...then there might be:
i) a decrease in level of mercury in the column with gas pressure (an increase in the other end)...this is because the gas is exerting a pressure (u can also consider P as force since the area is same) greater than that exerted by the atmosphere in the other end.
ii) an increase in level of mercury in the column with gas pressure (an decrease in the other end)
iii) mercury level remain same if the pressure is same as that by atmosphere..
hence all the measurements are compared with the atmosphere...try to figure out when (ii) can happen.

nor of ur links works...it says "server error."...and in ur second image, i could only see a description of the situation and the 4 options, but where is the question?

 

[GorgeousEyes]

if u hold the u tube with the mercury only (no gas connected), then u will see that the height on both of the columns will be same....this is because the atmosphere is giving pressure on both open end of the tube which are equal in size. now if u connect a gas supply to one end and the other is left open (atmosphere is still giving a pressure)...then there might be:
i) a decrease in level of mercury in the column with gas pressure (an increase in the other end)...this is because the gas is exerting a pressure (u can also consider P as force since the area is same) greater than that exerted by the atmosphere in the other end.
ii) an increase in level of mercury in the column with gas pressure (an decrease in the other end)
iii) mercury level remain same if the pressure is same as that by atmosphere..
hence all the measurements are compared with the atmosphere...try to figure out when (ii) can happen.

nor of ur links works...it says "server error."...and in ur second image, i could only see a description of the situation and the 4 options, but where is the question?

Thanks for ur explanation .. Here's the full pic

 

[sourov97]

Thanks for ur explanation .. Here's the full pic

to lift the stone...the clockwise moment (by F) should be greater than the anticlockwise moment ( by the weight of the stone)
moment = force * distance...here the force, weight of the stone is constant, so the smaller the distance the less the anti clockwise moment...
or u can also consider the clockwise moment....F can be smallest only if the distance is largest...

 

[GorgeousEyes]

T

to lift the stone...the clockwise moment (by F) should be greater than the anticlockwise moment ( by the weight of the stone)
moment = force * distance...here the force, weight of the stone is constant, so the smaller the distance the less the anti clockwise moment...
or u can also consider the clockwise moment....F can be smallest only if the distance is largest...

THANK YOU !

 

[$$AK$$]

In physics 0625/paper 1
can any body please help me with the thermal capacity questions in general
Thnx

 

[Iridescent]

In physics 0625/paper 1
can any body please help me with the thermal capacity questions in general
Thnx

Can you write any questions that find difficulty in?

 

[Gehad Mohamed]

can anyone help me with question 33

 

[CVB15]

can anyone help me with question 33

C, because:
as they are connected in series, 20 ohms+10 ohms= 30 ohms. So, the amount of voltage for the 20 ohms would be 20/30 * 12 = 8V. I can explain it again if u don't get this.

 

[Gehad Mohamed]

C, because:
as they are connected in series, 20 ohms+10 ohms= 30 ohms. So, the amount of voltage for the 20 ohms would be 20/30 * 12 = 8V. I can explain it again if u don't get this.

really thanks alot, i got it

 

[Fatum Zuh]

I need help...
http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Physics (0625)/0625_w10_qp_12.pdf
Question 1
The answer is B, but my question is how? Please explain to me.
Thanks.

 

[fatima hussein]

I need help...
http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Physics (0625)/0625_w10_qp_12.pdf
Question 1
The answer is B, but my question is how? Please explain to me.
Thanks.

This is not from me its from a person called CVB15 who replied to this thread before. Check page 250 for proof.

weight change= 3.0N-1.2N= 1.8N
No. of discs changed= 8-2= 6
if F=kx in this case, 1.8N=6k
take k to be the weight of one disc, so 1.8/6= 0.3N
Hope this cleared your doubt

 

[fatima hussein]

Can someone help me with http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Physics (0625)/0625_s08_qp_1.pdf question 34 and 37.. in question 37, shouldn't the voltage stay the same because the voltmeter is connected to the 100Ω so the 90Ω doesnt affect it? Am i wrong?
Also,http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Physics (0625)/0625_s07_qp_1.pdf question 39, i dont understand half-life can someone give me the rules for it? thanks!