OCR GCSE Physics Paper 4 (Higher tier) J249/04 - 23 Jun 2022 [Exam Chat]

what about energy dissipation, I wasnt sure and less repeats(only one set of results was there). I was a bit unsure.

my prediction for this paper would be 71-72/90, is that a grade 9 do you think(It's very unrealistic for the grade boundaries to rapidly spiral since examiners were told to be more generous)

they sound like reasonable reasons

what grade do you thiink you will get for this paper and in physics overall

This is my answer to my 6 marker. Please tell me and predict how many marks I will get

Car A is safer than car B because it travelled a longer distance than car B. I said that car B had a larger deceleration rate, which leads to injuries/accidents as it requires a large force. I said car A had a shorter deceleration rate so car B so less forces are acting on car A so less likelihood on injury. I said that the estimation deceleration rate for car A is 7 m/s2(-7 m/s2) by doing 14m/s x 2s = 28m(as braking distance) and 14m/s divided by 2 to give -7m/s2. I said that given both cars had the same thinking distance, car A had a greater braking distance than car B and as thinking + braking = stopping, car A had a greater stopping distance than car B. I said like the drivers reaction time is fairly constant, how speed is directly proportional to the square of distance and proportional to thinking distance and gave examples. I said like the driver must leave enough distance for it to stop to avoid any accidents. I also said that the car A had a longer change in momentum, time taken to stop is greater and car B had a shorter change in momentum. I also said that in reference to car B, driver might've unexpectly press onto the brakes which causes the car to stop unexpectedly which is extremely dangerous.

I waffled some bits, but I'm sure I included everything I could

this paper felt a lot better than paper 1 although that's because i began to understand physics as a whole partway through year 10, so i've only really understood P1-4 through revision, whereas i understood P5-8 from the day i was taught it. paper 1 felt decent but i know i made a lot of silly mistakes, i'm hoping that this paper will make up for them. i've gotten 9 in my few sets of mocks so i'm hoping for that

I felt like I did equally well in both papers. If you remember in paper 1, the circuits question, I said current halfs when switch closes because the current flows through the whole circuit and 10 ohms so 6/10 = 0.6 and p.d halves because each component has resistance of 3, so that means 6/2 = 3 as yeah, u get what I mean, both have resistance of 5 so total resistance doubles so p.d halves. I put 1.2A, 6V and 3V. Unfortunately, I might have made silly mistakes in both papers which isnt good especially when I want a grade 9 despite finding the test easy in some extent

In terms of frequency changing wavelength, I said sound A has wavelength half of sound B so it would have double the frequency of sound B wave given both sound A and sound B have the same wave speed. Sound A would transfer more energy(twice the amount of energy). I'm sure I've written more but cant remember my answer, so is that enough for 2 marks?

I said that, Wait was the frequencies on the table, I thought it said wavelengths??

i remember it as frequencies, one of us have misread it

does anyone else remember what it was?

I thought the question says how the frequency changes??, I remember 600 and 1200 though for sure

You know for the 2 marker on use the graph to calculate electricity supplied, did you put 7.17 x 10 power of 17. For the 2 marker, well actually I wrote 3 things separately just in case, I said, population increases over the years increasing demand of electricity, more technology is being developed, so technology more people are using them more frequently and more vehicles have been developed so more people drive frequently as well drive on vehicles, is that 2 marks enough. And also for the 3 marker on higher p.d, I said that higher p.d means lower current, meaning less energy is being lost especially due to heating effect, and it reduces power cost and is very effiicient. I said its a step-up transformer which increases the output voltage so voltage is higher than input voltage(And expanded). Is that enough for full marks for all questions do you think?

You know for the 2 marker on use the graph to calculate electricity supplied, did you put 7.17 x 10 power of 17. For the 2 marker, well actually I wrote 3 things separately just in case, I said, population increases over the years increasing demand of electricity, more technology is being developed, so technology more people are using them more frequently and more vehicles have been developed so more people drive frequently as well drive on vehicles, is that 2 marks enough. And also for the 3 marker on higher p.d, I said that higher p.d means lower current, meaning less energy is being lost especially due to heating effect, and it reduces power cost and is very effiicient. I said its a step-up transformer which increases the output voltage so voltage is higher than input voltage(And expanded). Is that enough for full marks for all questions do you think?

i can't remember the graph one, but i wrote the same for the transformer one. for the 2 marker i put about it being renewable and people becoming more aware of the environmental consequences, and fossil fuels will run out so people are switching to renewable etc

what did you get for the transformer calculation question i dont remember which coil we had to find but i remember it being 2 marks