When we consider a point charge q moving with a velocity `vecv` at a given time in presence of magnetic field `vecB`, the charged particle experiences a magnetic force `vecF_m = q[vecv xx vecB]`. The force was first given by H.A. Lorentz and is called the Lorentz magnetic force. The force depends on q, `vecv and vecB` and involves a vector product of `vecv and vecB`. The force acts in a side ways direction perpendicular to both the velocity and magnetic field and the direction is given by right hand thumb rule for vector product. Obviously force on a negative charge is opposite to that on a positive charge.
An electron enters a given region moving with an initial velocity `vecv = 12.5 hati m s^(-1)` where a unifomr magnetic field `vecB = B_0 hatj` is also applied. What is the direction of force experienced by electron due to the magnetic field?

Explanation

As per right hand thumb rule of vector product force is along -ve direction of z-axis.