Question

A series of light waves pass through a 200-nanometer gap in a wall. Identify which light wave diffracts the MOST?

• A. wave with 400-nm wavelength
• B. wave with 200-nm wavelength
• C. wave with 100-nm wavelength
• D. wave with 800-nm wavelength
• E. wave with 600-nm wavelength

Answer 1

The correct option is B wave with 200-nm wavelength

The essential condition for diffraction to occur is having the incident wavelength of the order of the dimension of the slit(i.e. $a\approx \lambda$)

Maximum diffraction would occur when the wavelength and dimension of the slit are exactly equal.