Physics, Chemistry and Biology: Post your doubts here!

[ZainH]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_w08_qp_03.pdf
in this paper i didnt get 5 b (iii)
please can some pone help me for this question
and can someone explain the saponification i am realy very confused! i would appreciate if some one can make it clear for me
JAZAK ALLAH khair!

Fats are are esters as far as I remember. They are made up of carboxylic acids and alcohols.
Im not too good in chemistry but the answer should be ester.

 

[za Shadow]

hi PLLLLLZZZZZZZZZ URGENT!!!!!!! NEED UR HELP GUYS
PLZZZZZZ with explanation

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Physics (0625)/0625_w11_qp_33.pdf

Q2)c) Q7)d)i) Q8)a)ii) c)

PLLLLLLLZZZZZZZZZZZZZZZZZZZ HELPPPPPP

one more question
if we have 2 stones: 1 heavy and the other is light and air resistance is present
WHICH ONE WILL FALL FIRST IF DROPPED TOGETHER???

1 --> HEAVY: because more mass so more gravitational pull so more weight

2 --> LIGHT: because less air resistance is acting on it while the heavy stone more air resistance is pushing it upward

WHICH ONE OF THE 2 AND IS MY EXPLANATION TO THAT ONE CORRECT??????????

THANKS U V.V.V.V.V.V.V.V.V.V.V.V.V.V.V.V.V.VERY MUCH

 

[redd]

is there any revsion checklist for biology available????
n wht do we have to prepare in classification chapter...???

 

[ZainH]

is there any revsion checklist for biology available????
n wht do we have to prepare in classification chapter...???

Here's one.
http://www.cambridgestudents.org.uk...ns_checklist_for_IGCSE_Biology_0610_FINAL.pdf

 

[redd]

Here's one.
http://www.cambridgestudents.org.uk...ns_checklist_for_IGCSE_Biology_0610_FINAL.pdf

ohhh...i need for o level....is dere any for gcse o level biology 5090 ??

 

[acid96]

take question 2c....
we should imagine that the light reached at 0 sec...i.e immediatly...then calculate time taken by sound to reach by using the equation
time=distance/speed....=>800/320=2.5
thats the time that sound take...it is said that:
the time for sound to reach is same as the one for stone to reach the sea right?
thus i think we can say that time for stone to drop=2.5 sec,where gravity=10 meter/sec square.....so we can use the equation
v=1/2 gt square(half*gravity*time square)..then v=.5*10*(2.5*2.5) which is equal to 31.25 m/s


and for heavy and light objects...both fall the same...unless light object is unable to resist the air ..i.e feather or so..but if it was atleast a small rubber ball...it falls the same time as bowling ball cuz gravity is 10 i think..not so sure xD

 

[ZainH]

ohhh...i need for o level....is dere any for gcse o level biology 5090 ??

Sorry, I have no clue if there is one.. I tried to google it but no real result :|

 

[redd]

Sorry, I have no clue if there is one.. I tried to google it but no real result :|

ohhkkk...thnku so much for ur try...

 

[za Shadow]

take question 2c....
we should imagine that the light reached at 0 sec...i.e immediatly...then calculate time taken by sound to reach by using the equation
time=distance/speed....=>800/320=2.5
thats the time that sound take...it is said that:
the time for sound to reach is same as the one for stone to reach the sea right?
thus i think we can say that time for stone to drop=2.5 sec,where gravity=10 meter/sec square.....so we can use the equation
v=1/2 gt square(half*gravity*time square)..then v=.5*10*(2.5*2.5) which is equal to 31.25 m/s


and for heavy and light objects...both fall the same...unless light object is unable to resist the air ..i.e feather or so..but if it was atleast a small rubber ball...it falls the same time as bowling ball cuz gravity is 10 i think..not so sure xD

THANKS A LOOOT 4 TRYING REALLY APPRECIATE IT U R THE BEST PLLZZZZ

CONTINUE

 

[gelato]

Wait...so a magnet cannot have the same poles (as in it cannot have both poles as north or south) but a ferromagnetic material can?
http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Physics (0625)/0625_s03_qp_1.pdf
In number 27, the final answer is A and the other poster told me that "The metal XY is attracted by both north and south pole. So, basically, it is just another ferromagnetic metal and NOT a magnet. So even if you switch it's sides it'll still be an ordinary metal and get attracted despite the pole "

Oh dear...I'm a bit confused now

 

[areebaization]

why doen't carbonmonoxide react with acids or alkali??

 

[user]

why doen't carbonmonoxide react with acids or alkali??

Assalamoalaikum wr wb!

It doesn't reacts, cuz it's neutral in nature...!

 

[sma786]

Physics help ..
http://www.mediafire.com/?k4k67e1mkdhezr4
Question 11 .. How is the answer C .. the volume is getting decreased so the pressure is supposed to decrease as well isnt it ??

 

[semsemhosam]

Wait...so a magnet cannot have the same poles (as in it cannot have both poles as north or south) but a ferromagnetic material can?
http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Physics (0625)/0625_s03_qp_1.pdf
In number 27, the final answer is A and the other poster told me that "The metal XY is attracted by both north and south pole. So, basically, it is just another ferromagnetic metal and NOT a magnet. So even if you switch it's sides it'll still be an ordinary metal and get attracted despite the pole "

Oh dear...I'm a bit confused now

exactly

 

[semsemhosam]

Wait...so a magnet cannot have the same poles (as in it cannot have both poles as north or south) but a ferromagnetic material can?
http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Physics (0625)/0625_s03_qp_1.pdf
In number 27, the final answer is A and the other poster told me that "The metal XY is attracted by both north and south pole. So, basically, it is just another ferromagnetic metal and NOT a magnet. So even if you switch it's sides it'll still be an ordinary metal and get attracted despite the pole "

Oh dear...I'm a bit confused now

they said ROD XY , and didnt say MAGNET XY , and if it was a magnet it was going to be repelled by one of the poles but it was attracted by both , so its just a piece of metal which isn't a magnetised , so the other end will obviously be attracted by the magnet

 

[semsemhosam]

Physics help ..
http://www.mediafire.com/?k4k67e1mkdhezr4
Question 11 .. How is the answer C .. the volume is getting decreased so the pressure is supposed to decrease as well isnt it ??

when your decreasing the volume and the mass of air in the cylinder is same means your compressing it , so the air molecules will have less space to move , so they hit the walls of the container more frequently increasing the pressure
hope that helps and best of luck

 

[kboss]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Physics (0625)/0625_s04_qp_1.pdf
q 24 of physics paper 1 2004
mark scheme says answer is c....i don't get that at all!!

 

[za Shadow]

hi PLLLLLZZZZZZZZZ URGENT!!!!!!! NEED UR HELP GUYS
PLZZZZZZ with explanation

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Physics (0625)/0625_w11_qp_33.pdf

Q2)c) Q7)d)i) Q8)a)ii) c)

PLLLLLLLZZZZZZZZZZZZZZZZZZZ HELPPPPPP

one more question
if we have 2 stones: 1 heavy and the other is light and air resistance is present
WHICH ONE WILL FALL FIRST IF DROPPED TOGETHER???

1 --> HEAVY: because more mass so more gravitational pull so more weight

2 --> LIGHT: because less air resistance is acting on it while the heavy stone more air resistance is pushing it upward

WHICH ONE OF THE 2 AND IS MY EXPLANATION TO THAT ONE CORRECT??????????

THANKS U V.V.V.V.V.V.V.V.V.V.V.V.V.V.V.V.V.VERY MUCH

 

[ninjas4life]

for Q1 c) you would do dist/time=800/320=2.5 s then use v=at where a is g because the stone is falling under gravity. so 2.5x10=25 m/s
Q7 i guess there should be no change in ammeter reading. it is only measuring the urrent across the 2 ohm resistor.
Q8a)(ii)it would move down on the left (-)ive side and up on the right(+)ive side (anticlockwise) because the motion of the coil is always normal to direction of flow of curent and at right angles to the magnetic field according to Fleming's left hand rule.

c) where there is current produced, e.m.f. is induced in the coil. direction of induced e.m.f. is such that it will cause effects to oppose the current. electric current is a fiorm of energy and when the coil is moved against the electromagnetic force work has to be done in overcoming this force. so the current or energy is graually reduced as it is needed in overcoming this electromagnetic force.

 

[gelato]

I don't get question numbers 7 and 16...anyone?
http://www.xtremepapers.com/papers/CIE/Cambridge%20IGCSE/Physics%20(0625)/0625_s10_qp_12.pdf

Is there such thing as asking too many questions?