Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

phys > physical quantities, units and measurements > Flashcards

physical quantities, units and measurements Flashcards

1
Q

2 aspects of phys quantities

A

1) numerical value (magnitude)
2. unit of measurement

e.g. height = 1.62 (magnitude) m (unit)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

6 + 1 SI units: summary

A

length - meter - m
mass - kilogram - kg
time - second - s
electric current - ampere - A
temp. - kelvin - K
amt of substance - mole - mol
(oos: luminous intensity) - candela - cd

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

list 6 + 1 base phys quantities: SI units

A

length, mass, time, electric current, temperature, amount of substance, (luminous intensity)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

length: name + symbol: SI units

A

meter, m: length

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

mass: name + symbol: SI units

A

kilogram, kg: mass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

time: name + symbol: SI units

A

second, s: time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

electric current: name + symbol: SI units

A

ampere, A: electric current

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

temperature: name + symbol: SI units

A

kelvin, K: temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

amount of substance: name + symbol: SI units

A

mole, mol: amount of substance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

(oos) luminous intensity: name + symbol: SI units

A

candela, cd: luminous intensity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

derived quantities def (unofficial) + eg

A

in terms of 7 base quantities (SI units)

eg. force: newton, symbol N, m kg s^-2
power: watt, W, m^2 kg s^-3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

notes on phys quantities presentation

A

1) use / instead of - when representing fractions in final quantity units
2) (-ve) power bc: removed / = unit moved over

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

all +ve prefixes summary: name, in figures, scientific notation, words, symbol

A

tera: 1 000 000 000 000: 10^12, 1 trillion, T
giga: 1 000 000 000: 10^9, 1 billion, G
mega: 1000 000, 10^6: 1 million, M
kilo: 1000: 10^3: 1 thousand: k

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

all -ve prefixes summary: name, in figures, scientific notation, words, symbol

A

deci: 0.1: 10^-1, 1 tenth, d
centi: 0.01

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

relationship betw. 10^(+ve)x and number of zeros?

A

x = number of zeros
e.g. 10^3 = 1000 (3 zeroes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

relationship betw. 10^ (-ve)x and number of decimal places?

A

x = total number of digits after decimal pt

e.g. 10^-3 = 0.001

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

relationship betw. 1/ (multiple of 10: x) and 0. …1?

A

number of zeros = number of digits after decimal point

1/1000 = 0.001

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

tera: in figures, scientific notation, words, symbol

A

1 000 000 000 000,10^12, 1 trillion, T

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

giga: in figures, scientific notation, words, symbol

A

1 000 000 000, 10^9, i billion, G

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

mega: in figures, scientific notation, words, symbol

A

1 000 000, 10^6, 1 million, M

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

kilo: in figures, scientific notation, words, symbol

A

1000, 10^3, 1 thousand, k (lowercase!)

22
Q

deci: in figures, scientific notation, words, symbol

A

1/10 or 0.1, 10^-1, 1 tenth, d

23
Q

centi: in figures, scientific notation, words, symbol

A

1/100 or 0.01, 10^-2, 1 hundredth, cmi

24
Q

milli: in figures, scientific notation, words, symbol

A

1/1000 or 0.001, 10^-3, 1 thousandth, m

25
micro: in figures, scientific notation, words, symbol
1/ 1000 000 or 1/10^6, 10^-6, 1 millionth, greek alphabet mu (u w an extra tail at the start)
26
nano: in figures, scientific notation, words, symbol
1/ 1000 000 000 or 1/10^9, 10^-9, 1 billionth, n
27
reading def
values obtained using a single judgement
28
how to determine uncertainty of a reading
(+-) half the smallest division of the scale, values recorded as such e.g. measuring cylinder marking out every 1ml, uncertainty = 0.5ml
29
summary: no. of judements, uncertainty, examples
1 judgement: ± 1/2 smallest div: ammeter, voltmeter, thermomether 2 judgements (measurement): ± 1 smallest div, protractor 1°
30
uncertainty of digital devices
- read directly off the screen
31
how should values read off instruments be presented?
- in the uncertainty: half OR the smallest division of the scale e.g. measuring cylinder w markings every 1ml = 43.0m instead of 43ml ruler w/ markings every 0.1cm = 0.1cm
32
measurement def
values obtained using diff. betw. judgement of two values e.g. using a ruler (start and end alignment)h
33
how to determine uncertainty of measurements
2 judgements: thus, uncertainty = smallest division of the scale (0.5 division for each reading) e.g. ruler to smallest 0.1cm, uncertainty = 0.1cm
34
resolution def
smallest division that can read off scale of instrument (resolution not equal to or affected by uncertainty)
35
diff betw. 2 types of precision (conceptual) | 1
1. measurement vs instrument 2. compared to others vs objective | personal pts
36
precision def | (there are 2)
1. reproducibility: measurement is precise if *close to other values* obtained by *repeating* determination using same procedure 2. smallest measurement possible using instrument (depends on no. of judgements made) e.g. meter rule: 0.1 precision (smallest div), 100cm^3 measuring cylinder: 0.5cm^3 (1/2 smallest div)
37
relationship betw. instrument's resolution and precision? ## Footnote + but is it guaranteed?
instrument w/ better resolution -> measure smaller interval -> *likely* give values closer tgt -> more precise intrument e.g. digital micrometer screw gauge (measures to 0.001cm) *more precise instrument* than digital calipers (0.01cm): measuring same object, digital // gives *more precise readings* than // or *reading has higher precision* ## Footnote likely: not guaranteed bc intrument might have manufacturing error or error in diff. force applied
38
accuracy def
correctness: measurement accurate if *close to true value* ## Footnote since true vlue of quantity never exactly known, accepted value commonly used as test of accuracy
39
error def | 2
* anyth that *causes* *measurement to differ* from true value * *amt* which measured value *differs from* true value
40
zero error def + notes ## Footnote + how to compensate, what to check?
when measuring instruments improperly calibrated: instrument displays non-zero reading when supposed to be zero ## Footnote - corrected reading = avg - zero error - when using digital instruments, ensure initial reading is 0
41
relationship betw. range, error, precision and accuracy?
range - precision erorr - accuracy | range (max - min value), error (measured - true value)
42
decimal places vs sig figs | what do they depend on? + which affects precision?
decimal places: unit used significant figures - precision of measurement made (independent of unit)
43
sig. fig. rules (5)
1. all non-zero digits (1-9): alw significant 2. zeros betw. 2 other significant (1-9): alw significant 3. trailing zeros (right) w/ decimal pt: significant 4. leading zeros (left) w/ decimal pt: not significant 5. trailing zeros w/o decimal pt: ambiguous | e.g. 40.01: 4 5.60: 3 0.021: 2 3500: either 2, 3, or 4
44
standard form/ scientific notation: presentation + which are significant digits?
- written as a X product of power of 10: (10^ sth +ve or -ve), 10 ≥ a ≥1 - all digits before multiplication sign: significant | e.g. 1.2 x 10^4: 2 sf 3.500 x 10^8: 4 sf 4.5.60 x 10^3: 3
45
implied values
- when making measurements, precision of instrument to be indicated w/ appropriate no. of dp | e.g. ruler measuring correctly: 12mm, 23.4cm, 30mm, 10.0cm incorrectly:
46
what does height = 1.6m mean and not mean? | - what's the range? - is 1.6m = 1.60m?
- value betw. 1.5m and 1.7m, but closest to 1.6 than 1.5 or 1.7 -> betw. 1.55m and 1.65 - not = to 1.60m: 1.60m means betw. 1.595 and 1.605
47
steps for unit conversion
e.g. converting from x -> y 1. separate number and unit 2. x in terms of y (e.g. 1g = 1/1000kg, or 1kg = 1000g) 3. sub in x-in-terms-of-y 4. complete calculation! e.g. 1.25g/cm^-3 in kg m^-3 1.25g/cm^-3 = 1.25 x [(1g)/ (1cm)^3] = 1.25 x [(1/1000kg) / (1/100m)^3] = 1.25 x [ 0.001kg / 0.000001m ^-3] = 1.25 x 10^3 kg m^-3
48
precision + use of meter rule, retractable steel measuring tape, cloth measuring tape
meter rule: straight length ≥ (up to) 1000m retractable steel measuring tape: straight length cloth measuring tape: length along curved surfaces precision for all: 1mm/ 0.1cm/ 0.001m
49
49

phys (1 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions