Question about wave properties of matter

[Moko]

Just wanted to know, what would be the accepted range b/w wavelength and slit width for diffraction/interference to occur? and would this apply to both electrons and photons?

Your help would be appreciated!

[Aurelian]

Just wanted to know, what would be the accepted range b/w wavelength and slit width for diffraction/interference to occur? and would this apply to both electrons and photons?

Your help would be appreciated!

I'm not entirely sure I understand the question, but as a general rule, significant diffraction will occur if the ratio of λ/w is approximately equal to or greater than one. This is a general principle which occurs for all instances of diffraction - including both electron and photon diffraction. Obviously in the case of the former, the wavelength in question would be the electron's de Broglie wavelength.