Maths: Formulae

Question 1

Magnification

Answer 1

Magnification = size of image /

size of real object

Question 2

Concentration factor

Answer 2

Conc factor = grade of metal in ore /

average crustal abundance

Question 3

Return period

Answer 3

Return period = no. of years on record + 1 /

number of events of that magnitude

Question 4

Lithostatic pressure

Answer 4

Pressure = density of rock x acceleration due to gravity
x thickness of overburden
Unit for Lithostatic pressure is Kg mˉ³

Question 5

What is rock density measured in?

Answer 5

g/cm³ (which is the same as tonnes/m³)

Question 6

Phi Scale

Answer 6

Phi = - log₂ (diameter of grain in mm /

1)

Question 7

Rate

Answer 7

Rate = change in quantity /

time taken

Question 8

Percentage change

Answer 8

Percentage change = new quantity / x100

original quantity

Question 9

Percentage yield

Answer 9

Percentage yield = actual amount / x100
theoretical or possible amount

Question 10

Surface area to volume ratio

Answer 10

Ratio = Surface area /

Volume

Question 11

Relative uncertainty in a value calculated by difference

Answer 11

% uncertainty = 2 x absolute uncertainty / x 100%

quantity measured