Calculate the momentum of a photon of wavelength 600 nm, in si units.

Two technicians are discussing how to test a car's exhaust by holding a small piece of paper within an inch of the tailpipe mouth. technician a says that if the paper is vibrating due to a "puffing" output from the tailpipe, this signals a smoothly running engine. technician b says that if the paper is being drawn toward the tailpipe, this could indicate burned exhaust valves. who is correct? a. technician b b. both technicians a and b c. technician a d. neither technicians a or b

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Which statements about the two fossil images are correct? 1. cave bears are ancestors of plateosaurus. 2. plateosaurus were present on earth before ostracoderms. 3. ostracoderms were the first to die. 4. plateosaurus died after the ostracoderms. 5. cave bears are the oldest fossils.