chap 1: measurement 📏

Question 1

what are the 7 base units

Answer 1

1. mass (kg)
2. time (s)
3. length (m)
4. electric current (A)
5. thermodynamic temperature (K)
6. amount of substance (mol)
7. luminous intensity (cd)

Question 2

what are the prefixes?

Answer 2

pico (p), nano (n), micro (μ), milli (m), centi (c), deci (d), kilo (k), mega (M), giga (G), tera (T)

Question 3

definition of systematic error

Answer 3

occurs according to some fixed rule or pattern such that they yield a consistent over-estimation or under-estimation of the true value of the measured quantity

Question 4

are systematic errors difficult to estimate and eliminate?

Answer 4

yes but if the cause of systematic error is known, steps can be taken to eliminate the error

Question 5

definition of random error

Answer 5

occurs without a fixed pattern such that a set of measurements done under the same conditions have an equally likely chance of being greater or less than the true value

Question 6

how can random error be reduced?

Answer 6

taking a large number of independent readings of a quantity (finding average)

Question 7

definition of accuracy

Answer 7

how closely a measured value agrees with the ‘true’ value

Question 8

does accurate mean relatively free of systematic errors?

Answer 8

yes (to find if it’s accurate ➡️ find average and if spread is +- 0.1, it is fairly accurate)

Question 9

definition of precision

Answer 9

how closely individual measurements agree with each other without reference to any ‘true’ value

Question 10

is being precise = small random error?

Answer 10

yes (to find if it’s precise ➡️ take average and see if it is +-0.01)

Question 11

to what s.f do we express absolute uncertainty to?

Answer 11

1 significant figure

Question 12

how many decimal places do we round to?

Answer 12

round off to the same number of decimal places as the absolute uncertainty