Uncertainties, Prefixes and Significant Figures Flashcards
pico (p)
x10 -12
nano (n)
x10 -9
micro (µ)
x10 -6
milli (m)
x10 -3
kilo (k)
x10 3
mega (M)
x10 6
giga (G)
x10 9
tera (T)
x10 12
rule for significant figures
answer should have no more than 2 more or 1 less significant figure than the value in the question with the least significant figures
best to answer with same significant figures as the question
how to ensure you get an accurate answer to a calculation
keep everything in your calculator as you go and do not round until the final answer
scale reading uncertainty in a digital scale
+/- 1 of the smallest division
scale reading uncertainty in an analogue scale
+/- 0.5 of the smallest division
what is an absolute uncertainity?
written as a value, not a percentage
how to work out % uncertainity
uncertainty/value x100
what percentage uncertainty should be used when calculating the uncertainty for an unknown variable
the highest % uncertainty in the known values
how to work out absolute uncertainty from percentage
simply multiply value by % (use % button on calculator)
eg: 31 x 4.8% = 1.5
when do random uncertainties come about
when we make repeated measurements of the same thing
equation for random uncertainty
Rand = max-min / n
how to make random uncertainty smaller
take more readings
dividing by a larger number
why do systematic uncertainties happen?
problems with the set up of the experiment
eg: a meter not calibrated correctly
graph of experiment with systematic uncertainty
straight line but does not go through origin