EXTRA - Key Equations For Physics IGCSE

Here I will be grouping together all the key equations for Physics IGCSE

Topic 1 - Forces and Motion

average speed = distance travelled/ time taken                             v = s/t

acceleration = change in velocity/ time taken                                a = (v-u)/t

force = mass x acceleration                                                           F = ma

weight = mass x gravitational field strength                                  w = mg

momentum = mass x velocity                                                        p = mv

moment = force x perpendicular distance from pivot                   moment = F x d

sum of anticlockwise moment = sum of clockwise moment

Topic 2 - Electricity

power = current x voltage                                                              p = I x V

energy = power x time                                                                   E = p x t

energy = current x voltage x time                                                  E = I x V x t

charge = current x time                                                                  Q = I x t

voltage = current x resistance                                                        V = I x R

Topic 3 - Waves

wave speed = frequency x wavelength                                          v = f x λ

law of reflection: angle of incidence = angle of reflection

law of refraction: refractive index,                                                  n = sin i/sin r                     (sin i = sin angle of incidence, sin r = angle of refraction)

total internal reflection: refractive index,                                        n = 1/sin c

Topic 4 - Energy

efficiency = useful energy output from system/ total energy output into system x 100

work = force x distance                                                                   w = F x d    

GPE = mass x gravitational field strenght x height                         GPE = m x g x h

KE = ½ mass x speed²                                                                    KE = ½mv²

power = work done/ time taken                                                       P = W/t     

Topic 5 - Solids, Liquid and Gases

density = mass/ volume                                                                   p = m/v

pressure = force/ are                                                                        p  = F/A

pressure difference = height x density x gravity                              p = h x p x g  (in liquids)

pressure is proportional to absolute temperature                           P1/T1 = P2/T2

Topic 6 - Magnetism

input voltage/ output voltage = primary turns/ secondary turns     Vp/Vs = n1/n2

none in Topic 7 - Radioactivity