A photon has a wavelength of 6.2 meters. Calculate the energy of the photon in joules. (Planck's constant is 6.626 × 10-34 joule seconds, the speed of light is 2.998 × 108 m/s)

what is the general relationship between a galaxy's distance from earth and its speed?

the answer is:

the farther away a galaxy is from us, the faster it is moving away from us.

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.