Unit Test Active
12
13
20
TIME REMAINING
47:22
Suppose the initial position of an object is zero, the starting velocity is 3 m/s and the final velocity was 10 m/s. The
object moves with constant acceleration. Which part of a velocity vs. time graph can be used to calculate the
displacement of the object?
o the area of the rectangle under the line
O the area of the rectangle above the line
O the area of the rectangle plus the area of the triangle under the line
O the area of the rectangle plus the area of the triangle above the line

Some material consisting of a collection of microscopic objects is kept at a high temperature. a photon detector capable of detecting photon energies from infrared through ultraviolet observes photons emitted with energies of 0.3 ev, 0.5 ev, 0.8 ev, 2.0ev, 2.5ev, and 2.8ev. these are the only photon energies observed. (a) draw and label a possible energy-level diagram for one of the microscopic objects, which has four bound states. on the diagram, indicate the transitions corresponding to the emitted photons. explain briefly. (b) would a spring–mass model be a good model for these microscopic objects? why or why not? (c) the material is now cooled down to a very low temperature, and the photon detector stops detecting photon emissions. next, a beam of light with a continuous range of energies from infrared through ultraviolet shines on the material, and the photon detector observes the beam of light after it passes through the material. what photon energies in this beam of light are observed to be significantly reduced in intensity (“dark absorption lines”)? explain briefly.