OCR Physics Unit 2 - G482 - (June Exams Preparation)

What have the grade boundaries been like for this Unit for a A or B throughout the years?

Could someone help me out with the significant figures and rounding in this question. For 1)b) ii) To calculate the resistance i used P=V^2/R , rearranged to give R= V^2/P and I just subbed in the values from the information they gave at the top of the page (230V,40W bulb). The answer I got was 1322 which I had to round to 1300 However the mark scheme uses R=V/I but it also says in the box next to it: accept 1322. Why does it accept 1322 and not my answer if this is the wrong amount of significant figures? Here is the mark scheme bit:

I did this a while ago to keep track

If the question gives values to two sig figs always give your answer to two sig figs

guys somebody make a revision list of all the experiments / things we need to know for long question answers!

G482 Jan '10 Q7b(ii)

Help please! Mark scheme isn't helping...

Could somebody explain how to do Q1c(i), what does it mean by potential divider I thought it was variable resistor, and Q1d(ii). Also for Q2b(i2) why do we minus and not add? And how do you do Q2c(iii) For june 2009 G482 paper?

I did, the mark scheme is not accepting my 2 sig fig answer, its accepting the 4 sig fig one!

1ci) Has to be a potential divider circuit, where you have a variable power source as you need to change voltage. A variable resistor doesn't change the source voltage, only the voltage across the component.
cii) Basically a straight, diagonal line upwards which starts at 10 ohms on the y axis. This is because the question says that at room temperature the resistance is 10 ohms, meaning that when current is 0, resistance is still 10 ohms.

2b i2) I have no idea sorry (I made the same mistake)

2ciii) You already worked out charge in Cii). energy = Charge x Voltage (from E=ItV, Q=It). Sub in values, use 14 as Voltage.
Hope this helps

1ci) Has to be a potential divider circuit, where you have a variable power source as you need to change voltage. A variable resistor doesn't change the source voltage, only the voltage across the component.
cii) Basically a straight, diagonal line upwards which starts at 10 ohms on the y axis. This is because the question says that at room temperature the resistance is 10 ohms, meaning that when current is 0, resistance is still 10 ohms.

2b i2) I have no idea sorry (I made the same mistake)

2ciii) You already worked out charge in Cii). energy = Charge x Voltage (from E=ItV, Q=It). Sub in values, use 14 as Voltage.
Hope this helps