Explain how atmospheric pressure come in existence

Astudent is given an assignment to demonstrate diffraction. he takes a photograph of a straw in a glass of water. the straw appears bent at the water level. which best describes this example? a) this is a good example of diffraction. b) this is an example of dispersion and not diffraction. c) this is an example of refraction and not diffraction. d) this is an example of reflection and not diffraction.

Because light travels in a straight line and casts a shadow, isaac newton hypothesized that light is

Which sound characteristic is not affected by the relative motion of an object