Chap 1: Physical quantities, units and measurement Flashcards
What is a physical quantity?
A quantity that can be measured
What is the 6 base quantity and their common symbols?
- length, l
- time, t
- mass, m
- temperature, T
- amount of substance, n
- electric current, i
What is the 6 SI base unit and symbols?
- metre, m
- second, s
- kilogram, kg
- kelvin, K
- mole, mol
- ampere, A
What is derived quantities?
Physical quantities that can be derived from base quantities
What is used to measure objects that are longer than a metre and the precision of it?
measuring tape, 0.1cm or 1mm
When do we use standard form?
for physical quantities with very big or very small magnitudes
What is the common prefix and conversion with symbols?
-nano, n —> 1nm = 1 x 10^-9m
-micro, µ —> 1 µm = 1 x 10^-6m
-mili, m —> 1mm = 1 x 10^-3m
-centi, c —> 1cm = 1 x 10^-2m
-deci, d —> 1dm = 1 x 10^-1m
-kilo, k –> 1km = 1 x 10^3m
-mega, M –> 1Mm = 1 x 10^6m
-giga, G –> 1Gm = 1 x 10 ^9m
-tera, T –> 1Tm = 1 x 10^12m
What is used to measure objects that are several centimetres to one metre and the precision of it?
metre rule, 0.1cm or 1mm
What is used to measure an object’s internal and external diameters and depths that are between 1cm and 15cm and the precision of it?
digital calipers, 0.001cm or 0.01mm
What is used to measure objects that are very small and its precision?
micrometer screw gauge, 0.0001cm or 0.001mm
What is parallax error caused by?
inaccurate positioning of the observers eye while taking readings
How to avoid having parallax error?
the eye should be positioned directly above the markings
What is zero error?
non-zero reading when we expect a zero reading
How to avoid having zero error?
Corrected reading = measured reading - zero error
What is used to measure quantity of time?
stopwatch
