7/21/2019 IGCSE Physics Equations

1/2

igcse Physics Equations

Topic Word Symbol

1 - Forces and

Motion

average speed = distance travelled(displacement) / 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

Orbital speed = (2 x pi x radius) / period of

orbit

orbital speed = (2x !x r) / T

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

voltage = current x resistance V = I x R

charge = current x time Q = I x t

3 - Waves wave speed = frequency x wavelength v = f x !

angle of incidence = angle of reflection i = r

7/21/2019 IGCSE Physics Equations

2/2

igcse Physics Equations

Topic Word Symbol

3 - Waves refractive index = sin angle of incidence / sin

angle of refraction

n = sin i/sin r

refractive index = 1 / sin of critical angle n = 1/sin c

4 - Energy efficiency = (useful energy output / total

energy output) x 100

work = force x distance w = F x d

GPE = mass x gravitational field strength x

height

GPE = m x g x h

KE = "mass x speed# KE = #mv$

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

5 - Solids,

Liquid and

Gases

density = mass/ volume p = m/v

pressure = force/ area p = F/A

pressure difference = height x density x

gravity

p = h x p x g (in

liquids)

pressure x volume = new pressure x new

volume.

p1 x V1 = p2 x V2

pressure / temperature (kelvin) = new

pressure / new temperature

P1/T1 = P2/T2

6 - Magnetism input voltage/ output voltage = primary turns/

secondary turns

Vp/Vs = n1/n2

7- Radioactivity ALPHA DECAY:Radium-226!Radon-222

+ helium-4 nucleus

BETA DECAY:iodine-131 nucleus!

xenon-131 nucleus + beta particle