wave equation

Wave speed equation (using frequency)

v = f * λ (Wave speed = frequency × wavelength)

Wave speed equation (using time period)

v = λ / T (Wave speed = wavelength ÷ time period)

Frequency equation (from time period)

f = 1 / T (Frequency = 1 ÷ time period)

Time period equation (from frequency)

T = 1 / f (Time period = 1 ÷ frequency)

Law of reflection

i = r (Angle of incidence = angle of reflection)

Refractive index (Snell's Law)

n = sin(i) / sin(r) (Refractive index = sin of incidence ÷ sin of refraction)

Refractive index (using speed of light)

n = c / v (Refractive index = speed of light in vacuum ÷ speed of light in medium)

Critical angle equation

sin(c) = 1 / n (Sin of critical angle = 1 ÷ refractive index)