Solution: Red light is emitted from a source at rest at a wavelength of 650 nm. How fast would this source have to be moving relative to you for you to see it as blue? Would it need to be moving towards or away from you?

Problem

Red light is emitted from a source at rest at a wavelength of 650 nm. How fast would this source have to be moving relative to you for you to see it as blue? Would it need to be moving towards or away from you?