Biology; Chemistry; Physics: Post your doubts here!

[Mayedah]

Correct!

Tht was easy

 

[ashiqbal]

WOW! complete question!!!
Seriously thats like jumping off Burj Khalifa here!
How can you get confidence to even show your friend the answer? Its CIE boss! Not any regular school exam.
Just thinking of it gives me the shivers!

i told him, not showed him

anyway, just posting some difficult MCQs, if someone could please explain:
s09 Q30
http://www.xtremepapers.com/papers/...onal O Level/Physics (5054)/5054_s09_qp_1.pdf
w09 Q29
http://www.xtremepapers.com/papers/...onal O Level/Physics (5054)/5054_w09_qp_1.pdf
w10 Q29
http://www.xtremepapers.com/papers/...nal O Level/Physics (5054)/5054_w10_qp_11.pdf

and could also post other difficulties i encounter as well if u guys want, as some MCQs might be easy for some but help others, so let me know!

 

[asd]

find the heat given out by 30kg ice at -42degreeC to bring its m.p , if s.p heat capaicity for ice is 2100 J/kgK-1 ??
ANSWER PLZ !!!

1.98*10^9

 

[Mayedah]

How? I asked for exlanation!

Take out the resistance of all three tht would be 7/4 now by formula u have to divide 4/7 t would be 0.57 !

 

[convent2012]

People, explain the ques below

A is answer because u see these are in parallel.

 

[ashiqbal]

I know it would be D because in the parallel combination of spring L is supported by 2 springs which means half acts on two springs
L= 2x

Since in seties combination of force L acts on each spring androduce an extension of 2x so it will be 4x which is
Pheww

i understand that the load is shared in the question, but in the second part, isnt the load shared by two springs?? so shouldnt it be 2x only?

 

[convent2012]

1.98*10^9

explain plz !!

 

[asd]

i told him, not showed him

anyway, just posting some difficult MCQs, if someone could please explain:
s09 Q30
http://www.xtremepapers.com/papers/CIE/Cambridge International O Level/Physics (5054)/5054_s09_qp_1.pdf
w09 Q29
http://www.xtremepapers.com/papers/CIE/Cambridge International O Level/Physics (5054)/5054_w09_qp_1.pdf
w10 Q29
http://www.xtremepapers.com/papers/CIE/Cambridge International O Level/Physics (5054)/5054_w10_qp_11.pdf

and could also post other difficulties i encounter as well if u guys want, as some MCQs might be easy for some but help others, so let me know!

1) Earth wire will make the casing live? LAst 2 are non-sense LMAO, and the first one can't be because eearth wire is at the wrong place, fuse won't blow.
2) Earth is always green as it is, and live brown.
3) They asked the electron flow, its always from -ve to +ve, and electron carries a -ve charge !

 

[asd]

explain plz !!

Mass x (temp difference + 273) x C
where C is the specific heat capacity!

 

[Mayedah]

i told him, not showed him

anyway, just posting some difficult MCQs, if someone could please explain:
s09 Q30
http://www.xtremepapers.com/papers/...onal O Level/Physics (5054)/5054_s09_qp_1.pdf
w09 Q29
http://www.xtremepapers.com/papers/...onal O Level/Physics (5054)/5054_w09_qp_1.pdf
w10 Q29
http://www.xtremepapers.com/papers/...nal O Level/Physics (5054)/5054_w10_qp_11.pdf

and could also post other difficulties i encounter as well if u guys want, as some MCQs might be easy for some but help others, so let me know!

Wo9 mcq 29 because these are the colours of the wires...mentioned in the book too ! N= blue E =green and yellow L= brown
W10 because the electron floe is always from positive to negitive while conventional current flows from positive to negitive !

 

[convent2012]

how temp varies from 30degreeC, if the gas is compressed from 50cm^3 to 25 cm^3 ????

 

[asd]

explain plz !!

You know the melting point for ice is O*C. So the temp difference will be 42. add 273 to convert into Kelvin (Specific heat is given in K unit)

 

[ashiqbal]

1) Earth wire will make the casing live? LAst 2 are non-sense LMAO, and the first one can't be because eearth wire is at the wrong place, fuse won't blow.
2) Earth is always green as it is, and live brown.
3) They asked the electron flow, its always from -ve to +ve, and electron carries a -ve charge !

but wont the high current flowing directly from live wire to earth wire cause a fire??

 

[asd]

how temp varies from 30degreeC, if the gas is compressed from 50cm^3 to 25 cm^3 ????

60*C ?

 

[asd]

but wont the high current flowing directly from live wire to earth wire cause a fire??

Aren't they covered? or are they naked? They are covered! So no fire.

 

[Mayedah]

i understand that the load is shared in the question, but in the second part, isnt the load shared by two springs?? so shouldnt it be 2x only?

In series the total load is 2x and this is shared by 2 springs so in parallel it would be 2x + 2x because the load is adding !

 

[convent2012]

what will be volume of a gas if pressure on it is released from 22mm-Hg to 12 mm-Hg ????

 

[ashiqbal]

Aren't they covered? or are they naked? They are covered! So no fire.

a short circuit will occur, will it not, when current flows from live wre to earth wire? the large amount of heat produced will melt the insulation and cause a fire. that is my theory.

 

[ashiqbal]

In series the total load is 2x and this is shared by 2 springs so in parallel it would be 2x + 2x because the load is adding !

is there any sort of notes for this?? becoz i havent read this ever!

 

[scouserlfc]

is there any sort of notes for this?? becoz i havent read this ever!

yup its correct i did this paper today and selected D AS THE answer too, i dont think anything special is there u just need to ponder like mad here and see the extensions how they are affected with one spring