Question:
If a beam of red light (wavelength = 0.65 micrometres) passes through a pinhole with diameter of 4 micrometres, what is the diameter of the spot on a wall 3 m beyond the pinhole?
Ans: 0.5 m
See attached explanation.
My question is, why can you multiply D by the angle to get lspot?
If a beam of red light (wavelength = 0.65 micrometres) passes through a pinhole with diameter of 4 micrometres, what is the diameter of the spot on a wall 3 m beyond the pinhole?
Ans: 0.5 m
See attached explanation.
My question is, why can you multiply D by the angle to get lspot?