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Physics, Chemistry and Biology: Post your doubts here!

C

Cartoco

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I'm having trouble with the definition of a transformer is it a device that converts an alternating current of a certain voltage without the change of frequency by electromagnetic induction
 
T

tweetie

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ramie majed said:
for 2i)
you have to mention that it starts to decay as bacteria starts to grow and spread, then it feeds on the leaf blade as it has the highest energy content then you have to say that the midrib vein and the branched veins are left out to the end because the midrib vein is the hardest and it's has the least energy content. and the smaller branched veins are left out not eaten.

1E)
1- take equal samples of the clot
2-add the buiret solution
3-maintain similar external conditions
4-take note of the colour changes from blue-turquoise/purple
5- compare the colors of the two diff clots. the one with the darker color has a higher protein content
for saftey measures use if 1- gloves 2- lab-coats 3-goggles

3a)

this is a test for respiration. so it moves because of the presence of the maggots! the maggots respire using the glucose in their body to form carbondioxide and water and this process is continuous and in respiration the amount of oxygen taken in will be replaced by the carbondioxide causing no or very less pressure accumulation but here theres soduim hydroxide which absorbs the carbon dioxide so this decreases the amount of gases in the air causing pressure this pulls the coloured drop making it move to the left so that it can replace the taken gases! and this process is enzyme dependent so it will vary if different external conditions were provided!
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thnxxxxx aloooooooot :D
 
Fady Soliman

Fady Soliman

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Hey folks, i am facing a problem with question 2 b, in the physics paper 32, o/n 2012, can anyone solve it and post it or jst tell me hhow to do it?
thnx
 
H

Heba Muneer

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Chemistry question, paper 6, November 11 :
Q6 : I don't get the need of pre-weighing and re-weighing. Because in my answer, I obtained the mass by evaporating water till crystallization point then dried the crystals and weighed them. And for the evaporation I wrote a test-tube instead

W11 QP.png
W11.png
 
sj0007

sj0007

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fbyfbyfby said:
how come http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Science - Combined (0653)/0653_s12_qp_11.pdf question 39 is C is and ques 40 is A?
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OH q 39 is soo easy you need a fuse rating greater than 10 A so the fire works and the most suitable option is of 13 A and remember that fuses are always connected in the live wire.
In 40 when S is closed an alternative way with lower resistance is provided for the current so it follows that and thus does not pass through the bulb.This path for current is also called a short circuit.
 
sj0007

sj0007

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Cartoco said:
I'm having trouble with the definition of a transformer is it a device that converts an alternating current of a certain voltage without the change of frequency by electromagnetic induction
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don't go with too much complicated language. just write it is a device which increases or decreases voltage by mutual induction....
 
fbyfbyfby

fbyfbyfby

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sj0007 said:
You have to make sure that the melting point of the substance is lower than 25 and boiling point is greater than 25......so that the substance is liquid at 25
Hope my replies helped
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thanl u very much! :) they helped so much.
 
A

Amaya Mangaldas

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Physics winter 2011, paper 3, variant 3:

question 7 d (i)
what does it mean for a 2 ohm resistor to be shorted out with a thick piece of wire?
and why will the ammeter reading stay the same?


Physics winter 2012, paper 3, variant 3:

question 1 (c)
why will the resultant force acting on the brick be acting upwards and not downwards?

Thank you!
 
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