Electrons are accelerated through a potential difference \( V_e \), and protons are accelerated through a potential difference of 4 V. The de-Broglie wavelengths are \( \lambda_e \) and \( \lambda_p \) for electrons and protons, respectively. The ratio of \( \frac{\lambda_e}{\lambda_p} \) is given by (given \( m_e \) is mass of electrons and \( m_p \) is mass of protons):