An electron moves through a uniform magnetic field B ⃗=B_0 i ˆ+2B_0 j ˆT. At a particular instant of time, the velocity of electron is u ⃗=3i ˆ+5j ˆm/s. If the magnetic force acting on electron is F ⃗=5ekN, where e is the charge of electron, then the value of B_0 is T.