(c) The laser pointer emits light because electrons in the material are excited (by a battery) from their ground state to an upper excited state. When the electrons return to the ground state, they lose the excess energy in the form of 532-nm photons. What is the energy gap between the ground state and excited state in the laser material?

Video transcript

Hello everyone. Today we have a phone problem. The laser pointer emits light because electrons and the material are excited by a battery from their ground state to an upper excited state. When the electrons return to the ground state, they lose the excess energy in the form of 532 nanometer photons. What is the energy gap between the ground state and the excited state in the laser material? So we need to solve for this energy gap. And I can use the equation that we have the energy is equal to planks constant or H multiplied by the speed of light or C divided by the wavelength. Now blinks constant can be found in a reference text and it is 6.626 times 10 to the negative 34 joules times seconds. And then the speed of light can also be found in the reference text is three times 10 to the 8 m per second. And we divide that by the wavelength that we were given. So we were given the wavelength in nanometers. So we have 532 nanometers, but we need to convert this into meters So we use the conversion factor that one nanometer is equal to one times 10 to the negative 9 m. Solving for the energy gap, we get the energy gap is equal to 3.7 to 3 times 10 to the negative 19 joules or answer choice D. And with that, we have solved the problem overall, I hope this helped. And until next time.