An electron with mass ‘\( m \)’ with an initial velocity \( (t = 0) \, \vec{v} = -v_{0}\,\hat{i} \; (v_{0} > 0) \) enters a magnetic field \( \vec{B} = B_{0}\,\hat{j} \). If the initial de-Broglie wavelength at \( t = 0 \) is \( \lambda_{0} \) then its value after time ‘\( t \)’ would be: