Q. Consider the following statements:
1.The refractive index changes periodically.
2.It occurs in nature in the form of structural coloration.
Which of the statements given above is/are correct regarding photonic crystals?

[A] 1 only

[B] 2 only

[C] Both 1 and 2

[D] Neither 1 nor 2

Answer: C
Notes:

Statement 1: Photonic crystals are optical nanostructures in which the refractive index changes periodically.

Statement 2: Photonic crystals occur in nature in the form of structural coloration and animal reflectors.

Source: PIB