Question

A proton and an electron both have a kinetic energy of 1 ev. Which has the longer wavelength? Neetprep

Answer 1

wavelength = h/momentum
where h is Plank's constant
momentum in terms of kinetic energy=
$\sqrt{2m \times kinetic \: energy}$
since, kinetic energy is same and h is a constant..
therefore wavelength is inversely proportional to
$\sqrt{mass}$
mass of proton is greater than electron
therefore electron has the longer wavelength!!