c
\(\,{v_y}\,\, = \,\,{u_y}\,\, + \;\,{a_y}t\,\, = \,\,0\,\, + \;\,\frac{{q{E_y}}}{m}\)\(=\frac{{{{10}^{ - 6}}\,\, \times \,\,{{10}^3}\,\, \times \,\,10}}{{{{10}^{ - 3}}}}\,\, = \,\,10\,\,m/s\)

\({v_x}\,\, = \,\,10\,\,m/s\,\,\therefore \,\,v\,\, = \,\,\sqrt {V_x^2\,\, + \;\,V_y^2} \)\(=\sqrt {{{\left( {10} \right)}^2}\,\, + \;\,{{\left( {10} \right)}^2}} \,\,\)

\(= \,\,10\sqrt 2 \,\,m/s\)