Early 20th-century physicist niels bohr modeled the hydrogen atom as an electron orbiting a proton in one or another well-defined circular orbit. when the electron followed its smallest possible orbit, the atom was said to be in its ground state. (a) when the hydrogen atom is in its ground state, what orbital speed (in m/s) does the bohr model predict for the electron? m/s (b) when the hydrogen atom is in its ground state, what kinetic energy (in ev) does the bohr model predict for the electron? ev (c) in bohr's model for the hydrogen atom, the electron-proton system has potential energy, which comes from the electrostatic interaction of these charged particles. what is the electric potential energy (in ev) of a hydrogen atom, when that atom is in its ground state? ev

Avector of magnitude 2 cannot be added to a vector of magnitude 3 so that the magnitude of the resultant is a. zero b. 1 c. 3 d. 5 e. 7

Certain bacteria (such as aquaspirillum magnetotacticum) tend to swim toward the earth’s geographic north pole because they contain tiny particles, called magnetosomes, that are sensitive to a magnetic field. if a transmission line carrying 100 a is laid underwater, at what range of distances would the magnetic field from this line be great enough to interfere with the migration of these bacteria? (assume that a field less than 5% of the earth’s field would have little effect on the bacteria. take the earth’s field to be 5.0 * 10-5 t, and ignore the effects of the seawater.)

You are a researcher for a golf club manufacturer. you are given two identical looking cubes of a metal alloy. you are informed that they are made of the exact same material, but one is crystalline, whereas the other is amorphous. it is your job to determine which one is amorphous this one is more stress-resistant and is useful in reinforcing golf clubs. which of the following is the best way to determine which is which? a. determine the density of each cube. the more dense one is the amorphous solid. b. melt both cubes and look for a broader range of melting temperatures. the one that melts over a broader range of temperatures is the amorphous solid. c. determine the density of each cube. the less dense cube is the amorphous solid. d. melt both cubes and measure the range of melting temperatures. the one that melts over a narrower range of temperatures is the amorphous solid.