When we consider the two-electron states of helium in perturbation theory, we take the e-e coulomb interaction to be the perturbation. a) what is the unperturbed energy and degeneracy of the multiplet of first excited states including spin? b) construct the states for 1-0, 3-1 and for 1-1, s 0 as properly symmetrized linear combinations of |space〉 |spin) c) without doing any calculation, which (if any) of the states in (b) have the lower energy when including the perturbation? give a physical argument justifying your answer.

You are the coordinator for a program that is going to take place at night in a rectangular amphitheater in the mountains. you will have no access to any electricity, but you must be able to illuminate the entire grounds. you know the intensity of the light from a lantern varies inversely as the square of the distance from the lantern. suppose the intensity is 90 when the distance is 5 m. a. write an equation to model the situation. b. solve for the constant of variation. c. write the equation to model the situation using the constant () of variation. d. you have been given lanterns with 40 light intensity. use your equation to solve for the distance from the lantern. e. you need to illuminate 225 km. how many meters do you need to light? f. how many lanterns will you need?

Substances that assume the shape of their container, but do not have a definite size are called

Abook is sitting on a table, completely still. what would happen if gravity suddenly stopped affecting the book? a. the book would move upward. b. the book would stay where it is. c. the book would fall. d. the book would move sideways.