A proton in a linear accelerator has a de Broglie wavelength of 122 pm. What is the speed of the proton?

An electron in a hydrogen atom relaxes to the n = 4 level, emitting light of 114 THz. What is the value of n for the level in which the electron originated?

Calculate the frequency of the light emitted when an electron in a hydrogen atom makes each transition. a. $n=4 \longrightarrow n=3$ b. $n=5 \longrightarrow n=1$ c. $n=5 \longrightarrow n=4$ d. $n=6 \longrightarrow n=5$

An electron traveling at $3.7 \times 10^{5}$ m/s has an uncertainty in its velocity of $1.88 \times 10^{5}$ m/s. What is the uncertainty in its position?

Calculate the de Broglie wavelength of a 143-g baseball traveling at 95 mph. Why is the wave nature of matter not important for a baseball?

An X-ray photon of wave length 0.989 nm strikes a surface. The emitted electron has a kinetic energy of 969 eV. What is the binding energy of the electron in kJ/mol? $\left[\mathrm{KE}=\frac{1}{2} m v^{2} ; 1 \text { electron volt }(\mathrm{eV})=1.602 \times 10^{-19} \mathrm{J}\right]$