When destructive interference occurs, the phase difference between two waves may be 5 pi.

Young’s double slit experiment proves that light contains photons with certain energy.

A laser beam with a radius of r hits an interface with an incident angle of theta i and gets refracted with an angle of refraction of theta t. The cross section of the refracted beam vs. the incident beam is cos (theta t)/cos (theta i).

In the double-slit experiment, if the distance of the two slits decreases, the bright fringes will all become closer.

One prefers to choose materials with strong absorption to fabricate a dielectric mirror so that the transmitted light can be minimized.

An unpolarized beam gets 50% reflection at an air-glass interface if the incident angle of the beam is at the Brewster angle.

The intensity of a spherical wave is reduced by two times when measured at 4 m away from the light source compared to that at 2 m.

An evanescent wave exists in the denser medium when total internal reflection occurs.

An unpolarized beam will be completely blocked by a polarizer.

When does a material undergo plastic deformation?