Original post by IdontlikeexamsI don't imagine many people will be able to come up with a mark scheme for this, as it was a hard paper so not many people will know every answer 😂 😂, but I remember the frequency was 20,000Hz (1 mark)
One of the calculations was like 1.3x10^12 (3 marks)
CT scans are still used because they provide very detailed images of the inside of the body (1)
They're used instead of ultrasound because they produce a more detailed image than ultrasound (1)
The train question) it is able to travel at constant speed whilst accelerating, as it's travelling towards the centre of the circle due to centripetal force, so the centripetal force causes it to accelerate towards the centre while keeping a steady speed (3)
It was track B, because the radius was larger, with less centripetal force, so the train could go around track B much quicker without toppling (2)
The train is made to tilt so it can travel faster without toppling (1)
Why did the train that had its line of action within the rails not topple - no resultant moment was made so the train didn't topple (1)
Centre of mass is the point at which the mass of an object is thought to be concentrated (1)
Two control variables (first question) same strength/size/direction of magnet and the paper funnel should be clamped at the same distance apart (1)
6 marker
Cba to write it all, but basically you name the parts of the eye and the roles they play in making an image, and where the image is formed for short sighted/long sighted people to make the image blurry (6)
Ultrasound question) it's measured by the distance from the entrance to the crack, and the reflection from the crack back to the Entrance (2)
What else do you need to know to measure the distance? The length of the wing or speed of the ultrasound (1)
Another way to measure stopping distance was to measure how high the weight went up (1)
3 conclusions about the refractive index of the glass of the two different lenses) diverging lens was more powerful, as the refractive index was greater for the same light intensity, the glass of the diverging lens had more curvature due to it being more powerful, the diverging lens' glass had a shorter focal length as shorter focal length means more powerful refractive index (really not sure on this one) (3)
Two factors that affect the power of a lens, focal length, refractive index or curvature (2)
The hydraulics question) liquids property is that they're virtually incompressible, (2)
Potato question: X should be drawn in the centre, in like with where the forks intersect (1 mark)
Pendulum: 5 (2/3 marks)
Angle of refraction: 12.34 degrees [It was something around this, might be 18.34?] (3 marks)
Eyesight: power of 1.5 [again can't really remember] and units of dioptres (3 marks)
Benefit of a changing refractive index lens: Saves money on glasses expense (1 mark)
I was very unsure in the rest of this question so no answers,
The last 2 questions) the relationship was inversely proportional, because as the value on the X axis went up the value on the Y axis went down, where the constant of k was 6000 causing y = k/x (add data) (2)
A computerised image is better because angle degree of tilt can be measured more accurately/ cheaper than building model/ can reset animation and alter potential events (1)
Light on a camera: CCD (Chraged Couple Device)
Hope this is alright I've missed a few questions so please add to it, I know missed a few calculations so feel free to add to it
I've probably got quite a bit wrong so correct me if I'm wrong
Grade boundary predictions the paper wasn't as hard as last year, but P3 tends to be lower than everything else and the paper was still difficult so
A*) 39
A) 33
B) 29
C) 24
D)19
E) 13
Enjoy ☺️