Diffraction occurs because 1.light must slow down to turn sharp ...

[Mimi]

Diffraction occurs because
  1.light must slow down to turn sharp corners, causing a phase difference; because of that phase difference, interference occurs.
  2.light spreads out after passing an edge, such as the edges of a slit, causing interference.
  3.the light from two monochromatic sources in phase with each other interfere.
  4.edges, such as those on a penny, cause the light to behave as if there were twice as many sources, and those virtual sources interfere with each other.

Question 2

Which of the following would not increase the radius of the dark fringes caused by the Newton's Rings effect?
  1.increase the radius of curvature of the lens and decrease its index of refraction
  2.increase the wavelength of the light and the radius of curvature of the lens
  3.use a lens with a larger index of refraction and smaller radius of curvature
  4.use a lens with a smaller index of refraction and increase the wavelength of the light

[juiceman1987]

Answer to Question 1

2

Answer to Question 2

3

[Mimi]

Thanks for the timely response, appreciate it

[brbarasa]

Great answer, keep it coming