Additional Questions

1. Researchers who investigate the properties of light use materials similar to the IR detector card. However, they sometimes need to detect only a small range of the energies in the infrared. Suppose such a card is created and it detects only photons with energies between 1.1eV and 1.2eV. Describe the energies of the bands of this material. Explain your conclusions. (Such materials exist but are much more expensive than the IR detector that you used.)
2. A rock music group has decided to use IR detector cards as part of its light show during concerts. Each ticket for the concert will have some infrared detecting material on it. During the concert big infrared lamps will flash; ticket holders will see nothing but the light coming from the tickets. However, the leader of the group would like some tickets to emit red, some to emit green, and some to emit blue light. As the scientific consultant to the group, your job is to determine whether this process is possible. Your first sep will be to see if you can arrange energy bands and gaps so that the IR detection material can emit only green photons or only blue photons. (We already know about red because we saw it happen.) What advise would you give to the group?