Physics - Controlled Assessment P2 Flashcards
Did we have any anomalous results?
No, all of our results fit the pattern which was a positive, non-linear relationship. All points were close to the line of best fit.
Yes
Identify anomalie
What’s its value?
Say that it doesn’t fit the pattern
No
Say all values follow the pattern and are close to the line of best fit
What’s the pattern
How do you draw a sketch graph?
Label the axis and draw the line
IDV on the bottom, DV along the y axis
Large varying results suggest it’s a non linear relationship
Equally spaced values suggest that it’s a linear relationship
How do you explain if case study 1, 2 and 3 support the hypothesis?
For each case study:
Yes / No
Write a description about the pattern they each show.
Mention if it changes the IDV or keeps it the same.
State data from each case study and identify anomalies.
E.g
Case study 1 and 3 support the hypothesis as c.s. 1 shows that, as light intensity decreases, due to the increase in distance between the lamp and LDR, the resistance increases.
It uses the same IDV however may not be very accurate as it was only trialled once yet, at 10cm the resistance was 45 ohms whereas at 50cm, the resistance was 87 ohms. This shows a positive non-linear relationship.
Case study 3 also supports the hypothesis as it uses the same IDV and displays that, as light intensity increases, the resistance decreases, displaying a negative non-linear relationship. However, there is an anomaly in trial 3 - 60 lux which may have effected the result.
This could be seen as a more accurate c.s. Since it was trialled multiple times to gather a mean average.
C.s. 4 doesn’t support the hypothesis as it uses a different independent variable - voltage.
Why does taking more readings improve an investigation?
Accurate mean average - reduces the effect of random errors.
Extend the range of readings - confirm what the maximum resistance might be.
Smaller intervals - more accurate line of best fit, closer to the true value, which can confidently be drawn.
Case study 4 example:
How do companies use data to decide on the most suitable LDR for a camera?
By carrying out investigations. In this case, you can see that the peak of LDR 1 is similar to that of a human eye.
LDR 1 therefore would be used an not LDR 2 since LDR 2 detects less light and it is at a higher wavelength than the human eye.
(Give data examples).
Do your results support the hypothesis?
Yes, the pattern shows that, as the distance between the lamp and the LDR increased (which decreased the light intensity), the resistance increased which demonstrated a positive, non-linear relationship on the graph.
We see this as, as 20cm apart, the resistance of the LDR was 0.37 ohms whereas at 100cm apart, the resistance was 2.83 ohms.
(Yes or no
Refer to pattern
Use evidence)
