In: Physics
An argon laser that has a wavelength of 455 nm shines on a double-slit apparatus, which produces an interference pattern on a screen that is 10.0 m away from the slits. The slit separation distance is 70.0 μm. (a) How many bright fringes are there on the screen within an angle of ±1° relative to the central axis? (b) How many dark fringes are there on the screen within an angle of ±2° relative to the central axis? Be careful to count all the fringes.
answer: a) 5 b)8, please explain how to get these correct answers.