Answer:
The distance that the diffraction spot moved on the screen is 0.314 cm
Step-by-step explanation:
The condition for maxima is equal:

Where
λ = 650 nm = 650x10⁻⁹m
D = distances = 1.87 μm = 1.87x10⁻⁶m and 1.94x10⁻⁶m
Replacing:


The distance that the diffraction spot moved on the screen is equal to:
