Uncertainties

Question 1

Percentage Uncertainty

Answer 1

Absolute Uncertainty divided by measurement
Multiplied by 100
Largest uncertainty is used when two readings are compared

Question 2

Random Uncertainty

Answer 2

Uncertainty associated with repeated readings of the same quantity
Largest reading - smallest reading
Divided by number of readings

Question 3

How to reduce random uncertainty

Answer 3

Carrying out more readings means dividing by a larger number so random uncertainty is smaller

Question 4

Systematic Uncertanties

Answer 4

To do with system set up
Eg A meter not being zeroed correctly results in all readings being out by the same amount
An experiment graph which is a straight line but does not pass through the origin
This is because each reading is out by the same amount

Question 5

Questions answered to

Answer 5

The same amount of significant figures as in the question

Question 6

Final uncertainty from a group of measurements

Answer 6

The largest percentage uncertainty

Question 7

Scale reading uncertainty

Answer 7

How well an instrument scale can be read
Uncertainty of +- in the last digit
Eg +-0.1v on a reading of 6.6v
+- 0.01 on a reading of 1.43v

Question 8

Absolute Uncertainty

Answer 8

The uncertainty in a measurement or calculation result
Eg +-0.1 on a reading of 6.6 Volts
+-0.01 on a reading of 0.21A

Question 9

Why you might expect a systematic uncertainty based on your graph of results

Answer 9

If the graph is a straight line which does not pass through the origin
Y-axis is not zero when X-axis is zero