what is the SI unit for current?
amperes (A)
what is the SI unit for temperature?
kelvin (K)
what is the SI unit for light intensity?
candela (cd)
what is the SI unit for time?
seconds (s)
what is the SI unit for mass?
kilograms (kg)
what is the SI unit for length?
metres (m)
what is the SI unit for pressure?
pascals (Pa)
what is the SI unit for amount of a substance?
moles (mol)
what is centi in standard form?
x 10⁻²
what is milli in standard form?
x 10⁻³
what is nano in standard form?
x 10-9
what is an error?
difference between measured value and true value
what is an uncertainty?
the range within which the true value is likely to lie
what does a random error cause?
readings to scatter due to unpredicted variations
how can a random error be reduced?
- repeating measurements
- taking a mean
how is the effect of random error shown on a graph?
increases scatter
what is a systematic error?
causes readings to be consistently too large or small
how to reduce systematic error?
- instruments recalibrated
- corrections or adjustments should be made to the technique
how are systematic errors shown on a graph?
offset of the line from the origin
what is a zero error?
systematic error which occurs when an instrument gives a reading when the true reading should be zero
how to reduce zero error?
taking a difference of the value from each value
what are precise measurements?
how close the measured values are to each other
what is an accurate measurement?
close to the true value
