# Why do we demand that $\lambda \ll \text{size of slit}$

I'd appreciate it if anyone could explain to me why do we demand that the wavelength will be much smaller than the distances between the slits in order to see wave diffraction when performing Young's experiment.

From searching online I've understood that if $$\lambda \gg d$$ where $$d$$ is the distance between two slits, then the maxima which occur every $$\lambda/d$$ will go out of the screen and we won't be able to see them. Is this correct?