In a ruby laser, an electron jumps from a higher energy levelto a lower one. If the energy difference between the two levels is 1.8 eV, what is the wavelength of the emitted photon? A) 469 nm
B) 649 nm
C) 694 nm
D) 964 nm

Alandscaper is shopping for landscaping materials. she wants to use materials through which water flows easily. which materials should she choose? check all that apply. clay gravel granite rocks with cracks loosely packed soil