How is the pressure of a gas related to its concentration of particles? a) pressure will expand a gas, enlarging its volume and reducing its density and concentration of particles. b) pressure will magnify a gas, developing its volume and multiplying its density and concentration of particles. c) pressure will compress a gas, reducing its volume and giving it a greater density and concentration of particles. eliminate d) pressure will accelerate a gas, extending its volume and allowing a smaller density and concentration of particles.

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.

You've already seen the value of 9.8 in this lesson. what's this value called? what quantity does it represent?

What causes the formation of ocean currents?