1. Write an expression for the energy of a single electron in a hydrogen-like orbit. Your expression should take into account a nuclear charge of Z and quantum number n. (b) Express your answer in Hartrees if the electron is in a hydrogen 1s orbital. (c) Calculate the energy in Hartrees of an electron in a helium 1s and a helium 2s orbital, neglecting the electron-electron repulsion term in the Hamiltonian.

Suppose a wire with a current is pushed upward by a magnetic field. how would the wire move if the direction of the current reversed? explain your answer.

Amass attached to a spring is displaced from its equilibrium position by 5cm and released. the system then oscillates in simple harmonic motion with a period of 1s. if that same mass–spring system is displaced from equilibrium by 10cm instead, what will its period be in this case? a mass attached to a spring is displaced from its equilibrium position by and released. the system then oscillates in simple harmonic motion with a period of . if that same mass–spring system is displaced from equilibrium by instead, what will its period be in this case? a) 0.5sb) 2sc) 1sd) 1.4s

What pressure difference is required between the ends of a 2.0-m-long, 1.0-mm-diameter horizontal tube for 40 c water to flow through it at an average speed of 4.0 m/s?