Determine the energy in joules of a photon whose frequency is 3.55 x10^17 hz

For ai it's atomic number is 13 and it's mass number is 27 how many neutrons does it have

How to convert a density of 0.791g/cm3 to lb/ft3

Look at the spectrums of a star moving towards earth and a motionless star. which of these is a correct inference that can be draw from the observation of the two spectrums? (2 points) the spectrum of a motionless star is difficult to be viewed separately using oridinary telescopes. the spectrum of a motionless star is identical to the spectrum of a star which moves towards earth. the spectrum of a star shifts towards the red region when the star moves towards earth. the spectrum of a star shifts towards the blue region when the star moves towards earth.