The de-Broglie wavelength of an electron moving with a velocity...

The de-Broglie wavelength, $\lambda=\frac{h}{m v}$ Here, $\quad \lambda_e=\frac{h}{m_e \frac{c}{3}} and$\lambda_p=\frac{h}{m_p c}$Given,$\quad \lambda_e=\lambda_p$So,$\quad \frac{h}{m_e \frac{c}{3}}=\frac{h}{m_p c}\Rightarrow \quad \frac{m_e}{m_p}=3$Ratio of KE$=\frac{K_e}{K_p}=\frac{\frac{1}{2} m_e v_e^2}{\frac{1}{2} m_p v_p^2}=\frac{1}{3} \left(\because \frac{m_e}{m_p}=3, $v_e=$\frac{c}{3}\right. and \left.v_p=c\right)