Working as a physicist Flashcards
(22 cards)
What does valid mean?
Measurements taken from an acceptable method and conclusions from it are realistic.
What does repeatablity mean?
An experiment that gives the same result when repeated by the same experimenter using the same method and equipment.
What does reproducibility mean?
An experiment that gives similar results when repeated by different experimenter using a different method and different equipment.
What is accuracy?
When measurements are close to the true value.
What is precision?
Measurements clustered closely together- consistency in repeated measurements.
What is resolution?
Smallest measurement that can be made using a piece of equipment.
What is systematic error?`
Systematic error is a consistant repeatable error due to equipment, method or technique.
What is random error?
Rnadom error is the unpredictable varying measurements. Can be reduced by carrying out repeated measurements and calculate mean.
What is zero error?
Zero error is systematic error due to non-zero reading when measuring and gives inaccurate values.
What is uncertainty?
Uncertainty is how at most a measurement can be off from its true value.
What is the uncertainty in analog and digital readings?
+- half the resolution
Why is uncertainty in timing NOT the resolution of the stopwatch?
Uncertainty for timing is by human reaction time so inaccurate.
Uncertainty IN a measurement?
At least +-1 smallest division
Uncertainty FOR a measurement?
Uncertainty for inital reading + Uncertainty for final reading
What are the ways to work out uncertainty in mean?
- Half range
- Half resolution (only in single reading or repeated same readings)
What do you do to the uncertainty when you multiply/divide measurements?
Add percentage uncertainty for each measurement
How do you work out fractional uncertainty?
Uncertainty/ Measurement
How do you work out percentage uncertainty?
Uncertainty/ Measurement X100%
What does a percentage uncertainty less than 5% show?
A percentage uncertainty less than 5% shows that it is repeatable.
What is uncertainty of time?
+-0.1seconds
What happens to the percentage uncertainty when you raise it to a power?
You multiply percentage uncertainty by the power number.
What is the formula for perentage difference?
Theoretical value- Experimental value/ Theoretical value X100%
