Light entering a small hole in a door would be an example of
a. reflection
b. refraction
c. diffraction
d. interference

Light entering  through a small hole in a door is an example if Diffraction.

Explanation:

Slight bending of light passing  through an edge or  opening  of an object is called as diffraction of light.  The rate of bending of light depends on the size of slit or opening in the object and relative size of light’s wavelength.

If the slit or the opening is much larger than the wavelength of the light, the bending  of the light will be almost  smaller and becomes unnoticeable. If  both the slit and the opening are equal in  size, the light bends to an considerable amount.There are two types of diffraction namely  Fraunhoffer diffraction and Fresnel diffraction.

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