Can someone check my answers ? ?

which of these is true about a bar magnet?

its north pole tends to point south.

its poles can be separated into two isolated poles.

its poles attract or repel because of their net electric charge.

> it attracts unmagnetized iron objects by making them magnetically polarized.

The nuclear potential that binds protons and neutrons in the nucleus of an atom is often approximated by a square well. imagine a proton conned in an innite square well of length 105 nm, a typical nuclear diameter. calculate the wavelength and energy associated with the photon that is emitted when the proton undergoes a transition from the rst excited state (n 2) to the ground state (n 1). in what region of the electromagnetic spectrum does this wavelength belong?