McQuarrie problem $2-3.$ Prove that $x(t)=cost$ oscillates with a frequency $v=\frac{}{2}.$ Prove that $x(t)=$Acos$t+$Bsin$t$ oscillates with the same frequency, $v=\frac{}{2}.$

What is the de Broglie wavelength of a $4\mathrm{.}20g$ bullet traveling at $965m{s}^{-1}?$

What is the minimum uncertainty in position of an electron whose uncertainty in velocity is $1\mathrm{.}0{10}^{5}m{s}^{-1}?$

The retina of the human eye can detect light when the radiant energy incident on it is at least $4\mathrm{.}0{10}^{-17}J.$ How many photons does this correspond to for light of $600nm?$

$($a$)$ Calculate the wavelength of light emitted when an electron falls from the $n=100$ orbit to the $n=99$ orbit $($Bohr model$)$ of the hydrogen atom. $($b$)$ Calculate the wavelength of light necessary to ionize a hydrogen atom $($corresponds to a transition from $n=1$ to $n=).$

The work function of rubidium is $2\mathrm{.}09eV.$ Can blue light $(470nm)$ eject electrons from the metal? If so$,$ what is the velocity of the ejected electrons?