An electron travels in a straight line from the cathode of a vacuum tube to its anode, which is 1 cm away. Its initial and final speed is 0 and 6.0*10^6 m/s respectively.
(a) Assume the constant acceleration and compute the force.
(b)Compare it with gravitational force on the electron which we neglect when we assumed straight-line motion. Is this assumption valid?

Do you agree with scientist’s prediction about the warming of alaska and other polar regions?

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.

Suppose a comet has an orbital period of 309.1 years around the sun. what is it’s average distance from the sun?