Physical Quantities Flashcards
Physical quantity
Anything that is measurable and can be expressed as a numerical number and unit
Types of physical quantities (2)
Base quantities
Derived quantities
Base quantities
Main quantities used to make all other quantities (metre, second etc.)
Derived quantities
Quantities found by either multiplying and/or dividing base quantities
What measuring tool is more accurate than a metre rule
Vernier Calliper (+-0.002 cm) (absolute uncertainty
Accuracy
Degree to which a measurement approaches the true value
Precision
Dependant on the measuring equipment’s smallest division on its measuring scale, the smaller the scale the greater the precision
Uncertainty of a measurement
The total range within which a measurement lies
Types of errors / uncertainties (2)
Systematic uncertainty
Random uncertainty
Systematic uncertainty
Caused due to incorrectly calibrated scale, eliminated by using a different tool
Zero error
the error a measuring instrument is reading when it should be on the zero mark
Random error
Errors by user, reduced by doing multiple readings and taking an average/plotting a graph. Results in scattered points around the line of best fit
Absolute uncertainty of protractor
1*
Uncertainty when it comes to time intervals
A short time interval has a large percentage uncertainty, the absolute uncertainty for time is heavily affected by the reaction time of the experimenter
What can we use to measure time (3)
Cathode Ray Oscilloscope
Stopwatch
Light gates connected to a time
