Measurements

Question 1

Base quantities (6)

Answer 1

CATTLM

1. CFurrent (amperes, A)
2. Amount of substance (moles, mol)
3. Time (seconds, s)
4. Temperature (kelvin, K)
5. Length (metres, m)
6. Mass (kilograms, kg)

Question 2

Conditions for equation to be homogeneous

Answer 2

Every term in the equation should have the same base units

Question 3

Prefixes

Answer 3

pico
nano
micro
milli
centi
deci
kilo
mega
giga
tera

Question 4

Order of magnitude

Answer 4

10^?
the ? is the order of magnitude

eg. 1000 = 10^3, order of magnitude is 3

Question 5

Systematic vs random error

Answer 5

systematic –> leads to readings that are always above/below the true value by fixed amount

random –> leads to readings being scattered about a mean value
- reduce by repeating measurement/finding average/plotting graph and finding best fit line

Question 6

Accuracy vs Precision
+ which error affects it

Answer 6

accuracy –> degree of closeness of the mean value of the measurement to the true value (systematic error)

precision –> degree of agreement between repeated measurements of the same quantity (random error)

Question 7

Absolute uncertainty to how many sf?

Answer 7

ONLY 1

Question 8

Absolute uncertainty sf dp rule for final ans

Answer 8

Absolute uncertainty is expressed to 1sf and quantity is expressed to same dp as the uncertainty `

Question 9

Uncertainty formulas

Answer 9

check notes but general summary

1. addition and subtraction (1sf)
   - add up all the absolute uncertainties multiplied by the no. of times of each thing
2. multiplication and division (2sf)
   - PERCENTAGE/FRACTIONAL uncertainty by adding up all the percentage uncertainties
3. Powers
   - PERCENTAGE/FRACTIONAL uncertainty by adding up all the percentage uncertainties multiplied by the mod of their powers

Question 10

Cosine and sine rule

Answer 10

check online

Question 11

What must u always label

Answer 11

Taking ____ and _____ as positive

eg. taking upwards and rightwards as positive