OCR Physics A Depth Unofficial Mark Scheme

Original post by dylan1016

Yeah I did too but people suggest thats wrong.

It is 100% not wrong. In this method we are not guessing which values to use. We used all of them. Also if pythagourous is used with original values youll get 30.6

who's fasting

I'm gonna die

For the conducting putty question, it asked "why would he use a large metal plate on either side" for 2 marks. I wrote a larger surface area would mean more current would flow, is that correct?

Reply 65

Original post by LauraGallery

For the conducting putty question, it asked "why would he use a large metal plate on either side" for 2 marks. I wrote a larger surface area would mean more current would flow, is that correct?

It's right, but you need to state the effect of it. Like hence It would reduce the effect of error,or something.

(edited 7 years ago)

Reply 66

Original post by XenoMJ

Question 4 for the percentage uncertainty I think it was 2% not 4% as you use +- 0.5mm not +-1mm. It says to the nearest millimeter so it would be to the nearest half a mm

Ocr accept both, it says so in the practical skills handbook.

Reply 67

Original post by mahmzo

It's right, but you need to state the effect of it. Like hence It would reduce the effect of error,or something.

I wrote to reduce contact resistance, I hope that's right. Btw for the next one did you write that you would check the ohm meter to see if the resistance had changed because then the area must have changed therefore the diameter.

Reply 68

Original post by Harrysomers1

Don't know if I got this one right aha but Personally, I wrote about how uv Ray's have more energy than visible light and hence they have a larger frequency due to equation e=hf. Also included threshold frequency in there. Then stated that as the electron will have more energy when uv light is used it will have a larger Ke max. Therefore it will have a higher velocity due to half mv2. Which was shown in the results as when velocity was used it moved much quicker, however they phrased it. Again, not sure if this is right, seen other people with different explanations

I think the reason it falls quicker is because of the one to one ratio, when intensity increased the number of photons per m^2 also rises so more photo electrons can escape per second >>falls faster.

Reply 69

Original post by Parhomus

I wrote to reduce contact resistance, I hope that's right. Btw for the next one did you write that you would check the ohm meter to see if the resistance had changed because then the area must have changed therefore the diameter.

I think that question will have a few answers, I wrote to use a Vernier gauge to check the diameter across a range of places. So did some of my friends. I did also say making sure not to apply to much pressure causing the playdough thing to change shape.

Reply 70

Original post by Parhomus

I think the reason it falls quicker is because of the one to one ratio, when intensity increased the number of photons per m^2 also rises so more photo electrons can escape per second >>falls faster.

The question asked how can it be sure that the diameter is constant so idk, was it a bit of a weird worded question haha, the way you are saying, it may be constant half way but then not the other half, it is hard to say without an unofficial mark scheme haha

Reply 71

Original post by mahmzo

I think that question will have a few answers, I wrote to use a Vernier gauge to check the diameter across a range of places. So did some of my friends. I did also say making sure not to apply to much pressure causing the playdough thing to change shape.

I thought they had put that ohm meter there for the purpose of that question. That's the only reason I wrote that.What was the question, asking how for it to retain its diameter or checking if it had changed?

Reply 72

esfio

1

Original post by XenoMJ

Question 4 for the percentage uncertainty I think it was 2% not 4% as you use +- 0.5mm not +-1mm. It says to the nearest millimeter so it would be to the nearest half a mm

+-0.5mm is the uncertainty in one measurement, yes, but when you measure using a ruler, you measure at two points, so the overall uncertainty in L is +-1mm
Then you work out the %Uncertainty in L and multiply by 2 for the %Uncertainty in L^2, giving 4.08% (3 S.F.)

(edited 7 years ago)

Reply 73

Original post by esfio

+-0.5mm is the uncertainty in one measurement, yes, but when you measure using a ruler, you measure at two points, so the overall uncertainty in L is +-1mm
Then you work out the %Uncertainty in L and multiply by 2 for the %Uncertainty in L^2, giving 4.08% (3 S.F.)

both are accepted

Reply 74

Original post by Parhomus

both are accepted

do you know If teachercol will upload the Depth Markscheme like he did for Breadth

Reply 75

Original post by mahmzo

do you know If teachercol will upload the Depth Markscheme like he did for Breadth

I hope so but I have no idea since he's made no mention as of yet.

Reply 76

chemari1

2

what do you reckon for an A?

Reply 77