light bending at a boundary is caused by differences in the speed if light in different materials. the greater the difference in speed, the more the light bends. you looked at three materials in this activity-air, water, and glass. in which two materials is the speed of light the most similar? explain your answer.

Strong conductivity of plasma allows it to act and react as and

The crust of earth may a- continets and ocean floors. b-continents only. c-layers of sedimentary rocks and continents. d-all of the above

Hot air balloons float in the air because of the difference in density between cold and hot air. in this problem, you will estimate the minimum temperature the gas inside the balloon needs to be, for it to take off. to do this, use the following variables and make these assumptions: the combined weight of the pilot basket together with that of the balloon fabric and other equipment is w. the volume of the hot air inside the balloon when it is inflated is v. the absolute temperature of the hot air at the bottom of the balloon is th (where th> tc). the absolute temperature of the cold air outside the balloon is tc and its density is ďc. the balloon is open at the bottom, so that the pressure inside and outside the balloon is the same. as always, treat air as an ideal gas. use g for the magnitude of the acceleration due to gravity.