ocr b physics paper 3

Heat the thermistor by submerging it in a beaker of water (mixed hot and cold water to control temp in multiples of 5 degrees) and measure T with thermometer in beaker.
The voltmeter was across the fixed resistor for two possible reasons (idk which they want): they want the output pd to increase as T increases, OR putting voltmeter across fixed resistor is easier than across the submerged thermistor.
Gradient was 39.1
Calibrating it you had to do y=mx +c so x=(y-c)/m in order to convert from V to T
For first six marker I talked about sensitivity and how the geometric mean (did it wrong, but you're supposed to do sqrt(top x bottom value) which were like 16 and 3 = about 7k ohm?) of the thermistor R range was the best for sensitivity. The actual Q value was about 9k ohm, so decreasing it to 7k would be best but past that it would be bad (and decrease output of V across all T) and increasing it would always be bad for sens but increase the output V for all T values.

The balanced has a reading when current going through wire because current creates a magnetic field which combines with the existing field to produce a force equal to BIL upwards on the wire and downwards on the magnet.
F=BL(I) can't remember the gradient but B = gradient/0.05 = 30mT

The same m/x for all pairs therefore m proportional to x, and since m proportional to force, x therefore proportional to force
Time period was 0.7 so natural frequency was 1/0.7 Mass was 0.7^2 x 39.2/4pi^2 = 485g or so
Second six marker I talked about varying the signal f and seeing how amplitude changes. amplitude graphed against ratio of driving freq to natural f gives resonance peak at driving f = natural f and much beyond that gives an amplitude less than without any driver at all.
Uncertainty in Force was 0.2N (half the max spread of the mass values*g)
Mean was 0.401
Top one wasn't outlier the lower one was
1/v=1/u+1/f
1=v/u+v/f (v/u=M)
M=-v/f+1
gradient of M-v graph was 6.67? = -1/f => f=0.15m
Power = 4 dioptre +- 0.2 (i think i did it wrong, I started the max and min lines from the same x value when actually the whole line was shifted up I think)

What questions did I miss?