Answer
The proton has the shorter wavelength.
Work Step by Step
The particles are not relativistic, so $KE=\frac{p^2}{2m}$.
Use equation 27–8 and form the ratio of the wavelengths.
$$\lambda=\frac{h}{p}=\frac{h}{2m(KE)}$$
Form the desired ratio. The kinetic energies are equal.
$$\frac{\lambda_p}{\lambda_e}=\sqrt{\frac{m_e}{m_p}}\lt 1$$
The proton has the shorter wavelength.
