The collision cross section s represents the effective target area "seen" by the asteroid and is found by multiplying (bmax)2 by π. if the asteroid comes into this area, it is guaranteed to collide with the earth. a simple representation of the cross section is obtained when we write v in terms of ve, the escape speed from the surface of the earth. first, find an expression for ve, and let v=cve, where c is a constant of proportionality. then combine this with your result for (bmax)2 to write a simple-looking expression for s in terms of r and c.

Consider the particle-in-a-box problem in 1d. a particle with mass m is confined to move freely between two hard walls situated at x = 0 and x = l. the potential energy function is given as (a) describe the boundary conditions that must be satisfied by the wavefunctions ψ(x) (such as energy eigenfunctions). (b) solve the schr¨odinger’s equation and by using the boundary conditions of part (a) find all energy eigenfunctions, ψn(x), and the corresponding energies, en. (c) what are the allowed values of the quantum number n above? how did you decide on that? (d) what is the de broglie wavelength for the ground state? (e) sketch a plot of the lowest 3 levels’ wavefunctions (ψn(x) vs x). don’t forget to mark the positions of the walls on the graphs. (f) in a transition between the energy levels above, which transition produces the longest wavelength λ for the emitted photon? what is the corresponding wavele

What does si stand for,when referring to a system of measurement

Two point charges are separated by a certain distance. how does the strength of the electric field produced by the first charge, at the position of the second charge, change if the second charge is doubled? a. the field does not change b. the field strength decreases by half. c. the field strength doubles d. the field strength quadruples