A particle A of mass $m$ and charge $q$ is accelerated by a potential difference of 50 V. Another particle B of mass $4 m$ and charge $q$ is accelerated by a potential difference of 2500 V. The ratio of de-Broglie wavelengths $\frac { \lambda _ { A } } { \lambda _ { B } }$ is close to:\\
(1) 0.07\\
(2) 10.00\\
(3) 4.47\\
(4) 14.14