Indicate the number and color of the photons emitted for each of the following electron transitions in hydrogen atoms:

(a) 1 e^– dropping from energy level 3 to 2 

(b) 10 e^– dropping from energy level 3 to 2 

(c) 100 e^– dropping from energy level 4 to 2 

(d) 500 e^– dropping from energy level 5 to 2.