A triply ionized beryllium ion, Be3+ (a beryllium atom with three electrons removed), behaves very much like a hydrogen atom except that the nuclear charge is four times as great. (a) What is the ground-level energy of Be3+? How does this compare to the ground-level energy of the hydrogen atom? (b) What is the ionization energy of Be3+? How does this compare to the ionization energy of the hydrogen atom? (c) For the hydrogen atom, the wavelength of the photon emitted in the n = 2 to n = 1 transition is 122 nm (see Example 39.6). What is the wavelength of the photon emitted when a Be3+ ion undergoes this transition? (d) For a given value of n, how does the radius of an orbit in Be3+ compare to that for hydrogen?
Physics 2 for Engineering Week 3 September 18 24 th th Metal sphere = conductor Charge comes to the surface Surface charge σ = Q / A Insulator Charge distributed over the volume ρ = Q / V Gauss’s Law Charges inside closed surfaces (Q = enclosed charge) ϕ is electric flux (electric field and area product with units N*m /C) 2 ϕ = E * A = Q / Ɛ 0 Gaussian surface must be symmetric For point or sphere charges, Gaussian surface has a spherical distribution For linear or sheet charges, Gaussian surface has a cylindrical distribution For a conducting sphere on the circumference E = q / (4πƐ R ) 0 2 Eon the inside of a conducting sphere =
