Point charge X has a charge of +3.5 x 10-9 C, and point charge Y has a charge of +9.5 x 10-9 C. The distance between the two charges is one meter. What will happen to the electrical force between the two point charges if the charge of X changes to +6.5 x 10-9 C and the distance between the two charges remains the same?
A. The electrical force of attraction will increase.
B. The electrical force of attraction will decrease.
C. The electrical force of repulsion will increase.
D. The electrical force of repulsion will decrease.

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.

While carrying a heavy box up the stairs, you set the box on a step and rest. then you pick up the box and carry it to the top of the stairs. describe these actions in terms of balanced and unbalanced forces acting on the box.

Look at the electroscope, describe how you can cause the two leaves at the bottom to repel each other and stay that way