How was physics p52

[saifookhan]

Hi I wanna ask how many marks will I lose if I messed up points on how to vary the independent variable and how to get the readings for independent/dependent variables? Assuming that I got other parts correct for question 1. Btw, I wrote "diameter of the wire of the metal coil" for the controlled variable, is it acceptable? Thanks in advance.

No. Your diameter thing will be wrong. Sorry.
You'll loose two marks.
Have you tried reading marking schemes? I suggest you to do it so you may get an idea on how markings are done.

 

[Geistpanzer]

Additional details: (This is perhaps more than what CIE demands, so don't worry if you don't have all of it)

-Note the phase difference between the V and I reading. (The constant L is the inductance of the coil)
-Use heat sink or water coolant to keep the temperature of the coil constant as it will affect resistance and the coil itself can expand due to heat.
-Use ohmmeter without power supply to measure the R of the coil.
-Calibrate the c.r.o with the same resolution display, time base, position, and amplification, make sure c.r.o is already grounded too.
-Use the same material with high melting point, for the loop.
-Use alternator as the signal generator or DC motor-generator coupling.
-Alternator should be able to vary its signal frequency.
-If using signal generator set up the function type to sin wave with desired frequency and voltage.
-Keep other magnetic field away.
-Use relay when controlling the circuit. (High current and high voltage danger)
-Add safety fuse in the circuit in case of overloading including ground clearance and etc.
-Use low resistance clamp when connecting the loop and the rest of the circuit. Make sure the connection is held strong to prevent fluctuations.
and many more.

 

[no.mercy]

Okay guys, here what i did for the design question.

I used a frequency oscillator to oscillate the coil, put two electromagnets on the sides. Emf induced or current induced was recorded on the CRO. Frequency was varied and the current was recorded.

 

[Geistpanzer]

Okay guys, here what i did for the design question.

I used a frequency oscillator to oscillate the coil, put two electromagnets on the sides. Emf induced or current induced was recorded on the CRO. Frequency was varied and the current was recorded.

Nice idea you got there, basically the same but you don't use alternator, you move the coil itself so that emf can be induced in that.

 

[FRENZYAMU]

Geistpanzer how do u knw all this, nd thankgoodness, i wrote the ohmeter point exactly like that

 

[batman345]

what if i used an oscillating magnet to induce current in the coil changed its frequency by changing the springs used as they have different spring constants? and i measure the frequency by connecting the coil to the CRO (which measures voltage) and an AC ammeter to record the highest current using the freeze motion video camera? ( the induction of AC is a right method?)

 

[batman345]

am i right please let me know

 

[balay]

in Q1....did the graph have a non-zero y intercept????

 

[AdeelRox]

Is this diagram correct for question 1?

 

[minie23]

Is this diagram correct for question 1?

YES !

 

[AdeelRox]

YES !

Dude what did ya write for additional points I wrote:
Take Several readings of I for for same f and average
the positive terminal of the ammeter and voltmeter must be connected to the positive terminal of the battery
the C.R.O must be correctly calibrated to give a graph on the screen, whose time period is measurable.
Take larger value current to reduce the uncertainity of the experiment.
are these fine?

 

[AdeelRox]

YES !

and to vary to frequeny I wrote use "different a.c supplies" is it correct?
For the value of E I accidentaly wrote the unit as NC^-1. Will I be penalised?

 

[AdeelRox]

I got it like (4.48+/-0.32) x 10^-6. then I got the value of E as, 3.57 x 10^4 or 3.37 x 10^3. dont remember exactly. then got the uncertainity as 9.64% and then V was (9.58+/-0.9) x 10^2

 

[rose1700]

Hey for additional details are these correct?
1. Allow the (I0)peak current to stabilize ?
2. Use small values of frequencies to get larger time period (it would help reading Io easily from CRO)

 

[Silent Hunter]

wat were units of E ?

 

[4hsan786]

wat were units of E ?

Vm^-1.

 

[Silent Hunter]

Vm^-1.

i think i also wrote same

 

[AdeelRox]

i think i also wrote same

would NC^-1 be penalised? in the marking schemes I saw many units.

 

[Silent Hunter]

would NC^-1 be penalised? in the marking schemes I saw many units.

in wich MS?

 

[AdeelRox]

in wich MS?

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_s10_qp_51.pdf
part 2(d), see its unit(s) in the marking scheme