Diffraction Basics

Diffraction is the bending of waves (like light) as they pass around an obstacle or through an opening. The amount of diffraction depends on the following:

* Wavelength (λ): Longer wavelengths diffract more than shorter wavelengths.

* Size of the opening (d): Smaller openings cause more diffraction.

The Answer

The hole with the smallest size will cause the light to diffract the greatest degree.

Explanation

Think of it this way:

* Large opening: If the hole is much larger than the wavelength of light, the light rays pass through relatively undisturbed, with little bending.

* Small opening: If the hole is similar in size to or smaller than the wavelength of light, the light waves have more opportunity to spread out as they pass through the opening. This spreading is diffraction.

In your example:

The light has a wavelength of 4.0 millimeters. The hole with the smallest dimension will cause the most diffraction.

Important Note: Millimeters are relatively large for visible light. Diffraction is most noticeable with wavelengths on the order of nanometers (billionths of a meter).