Determine the minimum energy of an electron which is trapped in a one-dimensional box (or the infinitely deep quantum well) with a length of 10 nm. determine the wavelength of monochromatic light that could excite the electron to its second excited state.

a charge 3q is at the origin, and a charge −2q is on the positive x axis at x=a. part a where on the x-axis would you place a third charge so it would experience no net electric force? enter an expression for the exact answer, which will involve a square-root sign. (do not enter an approximate decimal answer.)

the body's situation won't change the forces are equal opposit and on the same body

electric field is a function of 1/r^2

yes, the force per unit charge for a point charge is inverse square law.