in the double-slit equation,

*m* refers to the number of maxima from the central maximum

so an

*m* value of 2 would refer to the second maxima from the middle

* second maximum in this diagram

an m value of 3 for a red wavelength (third maximum) would be much further away than an m value of 1 (first maximum) for the violet wavelength

thus, when measuring the deviance,

*m *should be the same value for both red and violet wavelengths ~ otherwise the measurements would be quite unfair

now, knowing that both

*m *and

*d *are constants, the only variable is the different wavelengths, implying that the greater deviance of a red wavelength is due to its larger wavelength

*(an example)*
rearranging the formula,

m λ / d = sin θ

let

*m* = 1 ~

*(the first maxima from the central maximum)*
and

*d* = 0.05

for the red wavelength ~~ sin θ = (620*10^-9)/0.05

*whilst*
for a violet wavlength ~~ sin θ = (380*10^-9)/0.05

thus, θ for the red wavelength

*(as calculated) *is larger than the violet wavelength,

telling us that the red light diffracted more than the violet light

hope this helps!!