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In the coming oct/november 2013 session... btw are u like gud at other subjects as well like eco?
Fire away for Econ! Just, in the Econ thread.
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In the coming oct/november 2013 session... btw are u like gud at other subjects as well like eco?
Does anybody know the special criteria they have to give outstanding achievers award in biology?
For instance specific ways to answer the questions?
how about the graphs. does it need to be curves? or ruled lines?We have to use key words mentioned in the marking scheme and write accurate to-the-point answers.
how about the graphs. does it need to be curves? or ruled lines?
how about the graphs. does it need to be curves? or ruled lines?
today my teacher told us that we dont need to draw best fit curves in biology , that lines would do , but i really am not sure.
well the marking scheme does say that ur ans.s r correct... but could u EXPLAIN me how u got the and to b as i'm still a little confusedAlthough this is IGCSE and i did GCE but still i'll try to help
Q11.a) what this question gives idea to me that there is background radiation present which does not decreases the value below a certain limit! the background radiation might be caused by an other radioactive source present or the GM tube might be contaminated which causes the increase in readings! The sample might have been almost decayed NOT FULLY decayed!!
b) 52/2 = 26: 1st half life
15-13=2min,
15/26= 0.6,
=0.6+1
half life=1.6 (idk if this is correct ask someone)!!
c) although alpha would stop in air due to less penetrating power but gamma has very high pentrating power and it can reach the person and penetrate his body !
for b) think like 1st half life =52/2=26, 2nd half life=26/2=13, now the bottom line is on 15 so the product must have decayed before the second half life!! so the product decayed 2mins before so 15/26=0.6 half life now add both of the half lives!!
a) so see the graph, its going down and then it becomes constant. now you have studied that the graph keeps on going down when the product is decayed and the constant graph show there is another radioactive source present near somewhere which makes the reading constant!!
b) definately u have to learn that alpha has less pentrating power while gamma have high penetrating power. alpha can be stopped by thin paper and few centimetres in air which gamma can reach the person and move deep into the body of the person. this would kill the person's body cells and he might have diseases like skin cancer, sores etc Hope u understand it cox i made it extemely easy
this is included in the syllabus, i suggest you read your syllabus, so at least you won't be surprised by such questions in the paperohhhhh and what abt question 6 in this paper http://papers.xtremepapers.com/CIE/Cambridge International O Level/Physics (5054)/5054_s07_qp_2.pdf (sorry got physics tmrw :'( and i REALLY need ur help!,
P.S--> sorry if I'm troubling u ...
usama321 thanks! And this is my FINAL doubt from an igcse paper...http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Physics (0625)/0625_w10_qp_33.pdf Q-2this is included in the syllabus, i suggest you read your syllabus, so at least you won't be surprised by such questions in the paper
i) http://upload.wikimedia.org/wikiped...p_rule.svg/220px-Right-hand_grip_rule.svg.png
use right hand rule here. Actually the picture in the question is a bit unclear. There is a coil wound around the two lines shown in the pic, so that the current goes into the paper from above as the coil winds around the line, and then as it comes around the bottom, it once again tells us the direction of the current in the wound coil. using the right hand rule, we can see that the north is to the right of the coil. The rest is pretty self explanatory
part b i is quite easy
b ii) We know when direct current is passed through a coil, there is magnetic field produced, with north and south poles formed accordingly to the direction of the current. The same principle applies here, except the current is alternating, meaning its direction constantly alternates, therefore causing the magnetic poles to alternate at high speeds at the ends of the coils. Due to the alternating current, the magnetic poles produced at the ends of the coil constantly change.
This results in a constant attraction and repulsion from the permanent magnet that is present nearby. As a result, vibrations are produced, that is sound waves are produced
Hi,
Please enlighten me on the question no. 1. (d) and 4. (b) ii , (b) iii. of this paper http://olevel.sourceforge.net/papers/5054/5054_s13_qp_22.pdf
Thank you.
1.(d) for this the backward force would increase and become equal to forward force!
4.(b)ii) Microwaves (its a fact u have to learn it)
4.(b)ii) television satellite sends microwaves to the satellite above earth and microwaves move though vaccum above the and through air to reach it. Then satellite send signals back to earth which antenna's receives
Its is a specific factor that inhibits or prevents the rate of photosynthesis from increasing further, but this can change over time and condition..... Only a change to the limiting factor will increase or decrease the rate of photosynthesis.Hiii,please can you explain me what is limiting factor in photosynthesis.
tIts is a specific factor that inhibits or prevents the rate of photosynthesis from increasing further, but this can change over time and condition..... Only a change to the limiting factor will increase or decrease the rate of photosynthesis.
Possible factors are: Sunlight, Temperature, Carbon dioxide (these 3 are thye main ones, on which the questions are based almost all of the times... Though other minor factors may be.... availability of water and availability of minerals etc......
So for an example, if all other factors are in very high concentration/amount, but there is only a small amount of sunlight, so it becomes the limiting factor, as due to it the rate would not increase further, like now the excess CO2, water or minerals or chlorophyll will remain unused..... so only if the amount of the limiting factor is changed, will the rate of photosynthesis change accordingly!!!
Hope this helps!!
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