According to Bohr, an electron in an excited state could give off .....

Question

a continuous cascade of photons for a high-level transition.

Answer 1

I assume what you meant is ok but I would state it a little differently.

could give off a number of wavelenghts of energy when moving from a higher state to a lower state.
You may want to work on that to make it sound better.

Answer 2

ok,shat about
several photons in a series of transitions to the ground state