Units/uncertainty

Question 1

Tera

Answer 1

10 to the 12

T

Question 2

Giga

Answer 2

10 to the 9

G

Question 3

Mega

Answer 3

10 to the 6

M

Question 4

Kilo

Answer 4

10 to the 3

k

Question 5

Milli

Answer 5

10 to the minus 3

m

Question 6

Micro

Answer 6

10 to the minus 6

µ

Question 7

Nano

Answer 7

10 to the minus 9

Question 8

Pico

Answer 8

10 to the minus 12

p

Question 9

Femto

Answer 9

10 to the minus 15

f

Question 10

Standard units

Answer 10

s
m
kg
A
K (kelvin)
mol

Question 11

Thermodynamic temperature unit

Answer 11

Kelvin (K)

Question 12

Light intensity unit

Answer 12

Candela (cd)

Question 13

Amount of substance

Answer 13

mole (mol)

Question 14

Homogenous

Answer 14

Using the base units of each side to show that both sides are equal so the equation works

Question 15

Random error

Answer 15

Errors where the measurements vary from the true value by different amounts, cannot be avoided but are minimised by having more attempts

Question 16

Systematic error

Answer 16

Where the measurements vary from the true value by the same amount each time

Question 17

Accuracy

Answer 17

How close your answers are to the true value

Question 18

Precision

Answer 18

A measure of how close your results are to the mean

Question 19

Absolute uncertainty

Answer 19

Range/2 or the resolution if you only have 1 value

The interval that a value is said to lie in with a given level of confidence

Question 20

Percentage uncertainty

Answer 20

Absolute uncertainty/value x 100

Question 21

Combining uncertainties

Answer 21

For + or - add absolute uncertainties
For x or / add percentage uncertainties and convert back
For raising a quantity to a power multiply the percentage uncertainty by the power and convert back
For multiplying the answer by a value percentage uncertainty is the same or multiply absolute uncertainty by the factor

Question 22

Error bars

Answer 22

Represent uncertainty on a graph
Draw one line horizontally for x variable and vertically for y from each point

e.g.
     _
     |
|—x—|
     |
     -

Question 23

What to plot on a line graph

Answer 23

Points
Error bars
Line of best fit
Line of worst fit (steepest line that touches all y error bars)

Question 24

Absolute uncertainty in gradient

Answer 24

Positive difference between the gradient of lines of best and worst fit

Question 25

Percentage uncertainty in the gradient

Answer 25

(Absolute uncertainty/ gradient of line of best fit) x100

Question 26

Weight

Answer 26

A force due to gravity, measured in Newtons

Question 27

uses of g

Answer 27

The gravitational field strength, g = 9.81 Nkg-1

The acceleration due to gravity, g = 9.81 ms-2

Question 28

Force on base units

Answer 28

kgms^-2

Question 29

Anomaly definition

Answer 29

A data point that doesn’t follow the general trend

Question 30

Volume of a sphere

Answer 30

4/3 π r^3