1. Intro to Physics Units

The photoelectric work function of potassium is $2.3$ eV. If light that has a wavelength of $190$ nm falls on potassium, find the kinetic energy, in electron volts, of the most energetic electrons ejected.

The photoelectric work function of potassium is $2.3$ eV. If light that has a wavelength of $190$ nm falls on potassium, find the stopping potential in volts.

What would the minimum work function for a metal have to be for visible light ($380$–$750$ nm) to eject photoelectrons?

The photoelectric threshold wavelength of a tungsten surface is $272$ nm. Calculate the maximum kinetic energy of the electrons ejected from this tungsten surface by ultraviolet radiation of frequency $1.45\times {10}^{15}$ Hz. Express the answer in electron volts.

A photon has momentum of magnitude $8.24\times10^{-28}$ kg-m/s. What is the wavelength of this photon? In what region of the electromagnetic spectrum does it lie?

A laser used to weld detached retinas emits light with a wavelength of $652$ nm in pulses that are $20.0$ ms in duration. The average power during each pulse is $0.600$ W. How much energy is in each pulse in joules? In electron volts?

A photon of green light has a wavelength of $520$ nm. Find the photon's frequency, magnitude of momentum, and energy. Express the energy in both joules and electron volts.

The energy of the $2s$ state of lithium is $-5.391$ eV. Calculate the value of $Z_{eff}$ for this state.

Estimate the energy of the least strongly bound level in the $L$ shell of N²⁺.

The doubly charged ion N²⁺ is formed by removing two electrons from a nitrogen atom. What is the ground-state electron configuration for the N²⁺ ion?

The energies of the $4s$, $4p$, and $4d$ states of potassium are given in Example $41.10$. Calculate $Z_{eff}$ for each state. What trend do your results show? How can you explain this trend?

The $5s$ electron in rubidium (Rb) sees an effective charge of $2.771e$. Calculate the ionization energy of this electron.

A hydrogen atom in a particular orbital angular momentum state is found to have $j$ quantum numbers $\frac{7}{2}$ and $\frac{9}{2}$. If $n=5$, what is the energy difference between the $j=\frac{7}{2}$ and $j=\frac{9}{2}$ levels?

Calculate the energy difference between the $m_s=\frac{1}{2}$ ('spin up') and $m_s=-\frac{1}{2}$ ('spin down') levels of a hydrogen atom in the $1s$ state when it is placed in a $1.45$ T magnetic field in the negative $z$-direction. Which level, $m_s=\frac{1}{2}$ or $m_s=-\frac{1}{2}$, has the lower energy?

The hyperfine interaction in a hydrogen atom between the magnetic dipole moment of the proton and the spin magnetic dipole moment of the electron splits the ground level into two levels separated by $5.9\times {10}^{-6}$ eV. Calculate the wavelength and frequency of the photon emitted when the atom makes a transition between these states, and compare your answer to the value given at the end of Section $41.5$. In what part of the electromagnetic spectrum does this lie? Such photons are emitted by cold hydrogen clouds in interstellar space; by detecting these photons, astronomers can learn about the number and density of such clouds.