A metal frame is pulled out of magnetic field at a constant velocity LaTeX: \small \vec{v}v → by a force LaTeX: \vec{F}_{pull}F → p u l l. The metal frame has resistance R and the changing magnetic flux induces a current LaTeX: ii in the frame. The magnetic field acting on the induced current generates a force LaTeX: \vec{F}_BF → B. Neglect all other forces.

Materials will have different energies associated with the electrons inside them. this is related to how strongly bound they are by their work function. if we sandwich a material with a very low energy between two materials with a high energy, we create a trap for an electron. if this trap is very narrow in one direction in comparison to the others, this is approximately a 1-dimensional box that confines the electron. what is the lowest energy of an electron in the box if the thinnest direction across the materials is 4.81 nm?