Assume hydrogen atoms in a gas are initially in their ground state. if free electrons with kinetic energy 12.75 ev collide with these atoms, what photon wavelengths will be emitted by the gas?

11. you want to calculate the displacement of an object thrown over a bridge. using -10 m/s2 for acceleration due to gravity, what would be the total displacement of the object if it took 8 seconds before hitting the water?

An alpha particle with kinetic energy 12.5 mev makes a collision with lead nucleus, but it is not "aimed" at the center of the lead nucleus, and has an initial nonzero angular momentum (with respect to the stationary lead nucleus) of magnitude l = p0 b, where p0 is the magnitude of the initial momentum of the alpha particle and b=1.40×10−12 m. (assume that the lead nucleus remains stationary and that it may be treated as a point charge. the atomic number of lead is 82. the alpha particle is a helium nucleus, with atomic number 2.) what is the distance of closest approach?

Hunter is in lab. he clears a spot on his lab bench to start working. he also puts his lab coat and goggles on. he then identifies where all of the safety equipment is. he notices his station is next to the fume hood, which ventilates the chemicals stored there. the noise of the fume hood was bothersome, so hunter turned it off. which could be an error in his set-up? he should not turn off the fume hood.  he should wait to put on his coat until after the directions are given.  he should wait to put on his goggles until after the directions are given.  he should not sit next to the fume hood.