(2) Unconditionally, the incident light should be natural light, the emergent light intensity is (sin θ cos θ) 2× i0/2, and the light intensity is the maximum when the angle θ=45 degrees.

(3) Half-wave loss should be considered in the case of air splitting, and the edge is a first-order dark stripe.

1. A is k=3. According to the equal thickness interference formula, the film thickness is d=(3×λ 1)/2=Lθ.

So the wedge angle θ=4.8× 10-5rad.

2. The wavelength is changed to λ2=600nm, and 2d+(λ2)/2=3×λ2, that is, A is the third bright stripe.

3. The edge is a dark stripe and A is a bright stripe, so there are always three bright and dark stripes.