Ahydrogen atom emits a photon of wavelength 1879 nm. from what energy orbit to what lower energy orbit did the electron jump?

The frequency of the emitted photon is given by:

where
is the speed of light

So we find


And the energy of the emitted photon is given by

where  is the Planck constant
f is the frequency
Substituting, we find


If we convert this into electronvolts:


This is the amount of energy lost by the electron in the orbit transition. If we have a look at the values of the orbit energy in the hydrogen atom:
https://i.stack.imgur.com/6raba.jpg
We can see that this difference of energy corresponds to the transition between the orbit n=4 (-0.85 eV) to the orbit n=3 (-1.51 eV):

Answertraveling around a circular trackexplanation"traveling around a circular track" is the best answer as you could be traveling around a circular track at a constant speed. your velocity would therefore have the same magnitude but will always be constantly direction. since acceleration is the rate of change of velocity, the rate of change will only involve the direction of velocity and not the magnitude.wrong choices: "an object at rest" does not accelerate at all"increasing speed while traveling around a curve" means that the acceleration will not be constant due to only change in direction; it will be constant due to both magnitude and direction"an object in free fall" does not necessarily change direction 

Because the sun is the biggest and if the sun orbits the earth we will be dead probably