91Ó°ÊÓ

Show that $hc=1240eVnm$.

What is the electron configuration of the second excited state of lithium?

a. Is a $4p→4s$transition allowed in sodium? If so, what is its wavelength (in nm)? If not, why not?

b. Is a$3d→4s$ transition allowed in sodium? If so, what is its wavelength (in nm)? If not, why not?

An electron accelerates through a $12.5V$ potential difference, starting from rest, and then collides with a hydrogen atom, exciting the atom to the highest energy level allowed. List all the possible quantum-jump transitions by which the excited atom could emit a photon and the wavelength (in nm) of each.

$1.0×{10}^6$sodium atoms are excited to the $3p$state at $t=0$s. How many of these atoms remain in the $3p$state at

(a) $t=10ns$

(b)$t=30ns$, and

(c) $t=100ns$?

An excited state of an atom has a $25ns$lifetime. What is the probability that an excited atom will emit a photon during a $0.50ns$ interval?

What is the angular momentum of a hydrogen atom in

(a) a $6s$state and

(b) a $4f$state? Give your answers as a multiple of U.

What is the difference between the probability density and the radial probability density?

$1.0×{10}^6$atoms are excited to an upper energy level at $t=0s$. At the end of $20ns$, $90\%$of these atoms have undergone a quantum jump to the ground state.

a. How many photons have been emitted?

b. What is the lifetime of the excited state?

A hydrogen atom is in the $2p$ state. How much time must elapse for there to be a $1.0\%$ chance that this atom will undergo a quantum jump to the ground state?