What is diffraction? a)the increasing speed of a wave as it enters a new medium b) the bending of a wave as it enters a medium at an angle c) the increasing speed of a wave as it moves around an obstacle or through an opening d) the bending of a wave as it moves around an obstacle or passes through a narrow opening

D) the bending of a wave as it moves around an obstacle or passes through a narrow opening

Explanation:

Even though light travels in straight line, it will bend around objects if their size is comparative to its wavelength. This phenomenon is called diffraction.

Light will also bend if the light travels from one medium to another medium at an angle, but that is called refraction.

Diffraction occurs in one medium. Refraction occurs when light travels from one medium to another.

its c its is a mixture of gases