Physics, Chemistry and Biology: Post your doubts here!

[snipex]

Well its just that you try each organic vompound with 8 molecules of oxygen and see if it will be balanced or not.

 

[Tiffygirly]

I agree with you. It should be C. It says concentrated aqueous sodium Chloride....because it's aqueous hydrogen should be discharged at the Cathode,and hum Chlorine at the anode. What year is this? is it May/june 2009??

 

[Ayyan :D]

Chemistry doubt-
View attachment 32892
The answer is D, how come?
Chlorine is bubbled at anode so it should be red and at anode colourless at cathode since it is hydrogen??! 2009 winter-paper 12

D is right.
Because after Chloride ions get to Anode, they will escape as Chlorine gas.
Hydrogen ions will leave as Hydrogen gas on Cathode.
Leaving behind a solution of Sodium and Hydroxide ions.
That's an alkaline solution of Sodium Hydroxide. That's why the color of the Universal indicator will be Purple/Blue.

C is wrong. How will the bubbling of Chlorine make the Universal indicator RED?

 

[Faheen]

to which tissue does the palisade mesophyll cell belong to?

 

[Muskan Achhpilia]

I agree with you. It should be C. It says concentrated aqueous sodium Chloride....because it's aqueous hydrogen should be discharged at the Cathode,and hum Chlorine at the anode. What year is this? is it May/june 2009??

2009 winter-paper 12

 

[sanya ahuja]

Chemistry doubt-
View attachment 32892
The answer is D, how come?
Chlorine is bubbled at anode so it should be red and at anode colourless at cathode since it is hydrogen??! 2009 winter-paper 12

The answer is D because the solution is concentrated. It has OH- AND H ions too. H being less reactive than sodium gets deposited on the cathode thus it is colourless. At the anode , purple colour is formed due to the presence of an indicator.

 

[Muskan Achhpilia]

Physics-
Which form of energy is used to generate electrical energy in a tidal power station?
A chemical energy
B gravitational energy
C internal energy (thermal energy)
D nuclear energy

Please explain and thanks a tonne!

 

[Muskan Achhpilia]

Physics doubt-
The answer is A(Summer 2006 paper 1)

 

[Faheen]

how do we mark the correct option on the mcq answer sheet......do we circle or do we shade??? also do v use a pencil or a pen to do that... plz help

 

[Alina Fahim]

http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Physics (0625)/0625_s10_qp_31.pdf

last question. Question 11, Part (b)

 

[Alina Fahim]

View attachment 32929
Physics doubt-
The answer is A(Summer 2006 paper 1)

ok, i'll try my best at it.

So, the formula for calculating thermal capacity is "c=Q/delta T
c- thermal capacity
Q- Quantity of heat needed to raise temp from T(initial) to T(final)
delta T- change in temperature. (which in this case will be the rise in temperature)

so if u substitue, assuming Q is kept constant, "c"(thermal capacity) of the first block is the greatest.

 

[Madiez]

how do we mark the correct option on the mcq answer sheet......do we circle or do we shade??? also do v use a pencil or a pen to do that... plz help

In the original CIE exam, the MCQ sheet shows a 'Directions' Bar on the left side of the paper which shows how to mark your choice.
On other papers (if you mean to ask about school MCQ sheets), it depends on what type of answer sheet they give you.
And, to be honest, i guess the 'School MCQ sheets' don't matter much.

 

[ParamoreEnthusiast86]

Can someone please post me a website for the Cambridge IGCSE Physics guide. PLease!!!! Thank you!!!

 

[amnakhan]

I don't have many questions but I need Proper notes for these as I am a bit confused on these topics,can someone PLEASE help:

• Moments(turning effects)
• Lenses
• Electrical Field Lines
• And,The Pressure law,Charle's Law & Boyle's Law

Your help is NEEDED URGENTLY & WILL BE HIGHLY APPRECIATED
Thank you !

 

[amnakhan]

how do we mark the correct option on the mcq answer sheet......do we circle or do we shade??? also do v use a pencil or a pen to do that... plz help

I am not sure if we circle or shade in the MCQ paper sheet but I'm SURE that you have to use a PENCIL .

 

[Ayyan :D]

Physics-
Which form of energy is used to generate electrical energy in a tidal power station?
A chemical energy
B gravitational energy
C internal energy (thermal energy)
D nuclear energy

Please explain and thanks a tonne!

B Gravitational Energy. Tides are produced due to the pull of the moon, which is due to the moons gravity.

 

[Ayyan :D]

I am not sure if we circle or shade in the MCQ paper sheet but I'm SURE that you have to use a PENCIL .

Shade with the pencil, on the correct box on the answer sheet.

 

[princevegeta]

How can a straight wire produce a Magnetic field?

 

[Nabeel.Ahmad]

How can a straight wire produce a Magnetic field?

If current flows through a wire, it aligns the magnetic domains within the wire, making the wire develop a magnetic field.

 

[princevegeta]

If current flows through a wire, it aligns the magnetic domains within the wire, making the wire develop a magnetic field.

Thanks i knew it. But wasn't able to put as the examiner wanted it.