IGCSE/GCSE/O & A Level/IB/University Student Forum
Qualification => Subject Doubts => GCE O - Level => Sciences => Topic started by: Twinkle Charms on May 24, 2010, 05:29:21 pm
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So have a look in here, got some predictions...
TO BE NOTED : THESE ARE ONLY PREDICTIONS, PLEASE DO NOT RELY ON IT 100%. DO SO AT YOUR OWN RISK.
First you can get the electricity question, big one. You will have to setup a circuit with a power supply, ammeter, voltmeter, semi-conductor diode, LED/Resistor and dip the diode in cold water or ice cubes. You will need to measure the temperature with a thermometer before starting to take readings. You will need to vary the voltage and take 5 or 6 readings from the ammeter and voltmeter, draw a table and plot a graph etc.
For the second question, it will be regarding the terminal velocity of two beads when they are dropped in a cylinder filled with oil. You will need to measure the diameters of the beads with a Micrometer Screw Gauge, so do learn how to use it. Next you will need to drop the beads one by one and note the time it took for the beads to travel a certain distance. You will need to measure this distance with a meter rule. Then error and improvements etc.
The schools/centers are not that rich to provide you with a digital one? Why would they teach us how to read off the values from a manual one in O Level and AS Level if they wanted to hand us the digital ones?
Thus, I suggest you learn how to use both vernier calipers and micrometer screw gauge and forget about it being a digital one!
Just stay focused, try to do the first experiment within one hour, take the 6 readings ASAP so that you can even come back to do the first question after finishing the second small/not so lengthy question. Yes you will be able to come back after you are done with the second question and finish the first one. You just won't have the equipment anymore. So you have 2 hours to do 2 questions, use the time wisely!
Another thing, you will need to keep the temperature constant, but don't try to take temperature readings more than two times, it's waste of time. Just do it once in the beginning and note it, then in the middle of the experiment read it again. The temperature should remain almost constant, but try to take the readings ASAP and turn off the power supply each time you have taken the reading. That's because at higher voltages, you will start to hear crackling noises from the water, but don't be alarmed and take the reading quickly and turn the power supply off.
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For What Variant Are These Predictions?
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opps forgot to mention that, variant3
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there is no variant 33 it is only 31 and 32
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opps forgot to mention that, variant3
Oh, i take 31, but thanks anyways still useful :)
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there is no variant 33 it is only 31 and 32
i got my timetable ryt in front of me n it say clearly 9702/33
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not really sure about that but if it's written in ur statement it's surely right :D
lol
where r u taking ur exams zara ??
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not really sure about that but if it's written in ur statement it's surely right :D
lol
where r u taking ur exams zara ??
Dubai
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nice :D
hey zara i don't think that's exam predictions ;)
that's surely the whole exam and with every detail
i wish i was taking that exam :P :D
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hii .. am doing 33 too . but who told u about these predictions ??
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Wow, seems really tough.
31 varient seems easier which im giving...
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nice :D
hey zara i don't think that's exam predictions ;)
that's surely the whole exam and with every detail
i wish i was taking that exam :P :D
really? if tht is, its great...buh i got it as predictions from someone...anyways...
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hii .. am doing 33 too . but who told u about these predictions ??
i got it from some other forum so thought of sharing.
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could you explain me how to use the LEDs and Semi conductor diodes?
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yh plz if u can explain LED .. ??? ??? ???
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Semi conductor diode is a device that will conduct current in one direction only
LED Light Emitting Diode, which glows when current passes through it
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so the graph is..
wat is on x-axis nad wat is on y-axis??
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any particular way of connecting the diodes?
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@scorpian dont worry theyll tell you what to take on y and x axes.
@coco pops yes ofcourse, u have to connect positive terminal of the diode to the positive of battery cz if u do it vice versa....the diode will not work
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i hve never used a power supply before..how do we vary voltages o power supply?
and i dont understand..wht the diode is for
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i hve never used a power supply before..how do we vary voltages o power supply?
and i dont understand..wht the diode is for
huuh?? didnt u practise any of the experiments in lab?? :o
anyways you can vary the voltage by variable resistor, and the experiment is about diode, so its for that lol
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You ripped this off xtremepapers' forums P:
By the way, this is for paper 33.
yeah
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@diablo any idea of 34 varient?
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hey..any idea whats coming in varient 31? im clueless :(
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hey..any idea whats coming in varient 31? im clueless :(
uh nop :-\
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how do you know how many significant figures to quote?
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how do you know how many significant figures to quote?
whatevr s.f you are usuing intially be consistent with it till the last of that question for all the values, for example if you took 3 s.f for your first reading, then for all the other values write them correct to 3 s.f.
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So basically the initial number of significant figures that I should use is my own choice but what matters is that i should keep them the same for the values calculated from the raw values?
For example I am recording the diameter of a ball using a micrometer or a v.calliper, then using 3 significant figures in both cases would be right?
What about thermometric readings? Will, say, 31.2 degree C be okay?
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Paper 31 is most likely to have 1 circuit related question and another mechanical question (oscillations, pendulum, etc).
I heard that there's going to be an oscillation question(mechanical question) and something regarding a magnet and thread in paper 34.
This information is merely based on what the vast majority are saying.
Good luck everyone....
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okay for the second question, errors and improvements :
Errors
1. small air bubbles are formed on the marble/spheres/(any balls being used) which hindered the motion of the ball
2. two sets of reading not enough to draw a valid conclusion
3. human error in timing
4. marble may have not reached terminal velocity
Improvements
1. release the ball/marble just a few mm above the oil surface
2. take more readings and plot a graph
3. use light gate to trigger stopwatch/high speed camera with known time intervals/use video camera with slow motion replay
4. ensure the terminal velocity by increasing the release height/using long tube/measure velocity at two intervals to check terminal velocity reached.
ALL THANKS TO XTREMEPAPERS.NET.