Acceleration is the time rate of change of velocity. Acceleration is a vector, so this means it has both magnitude and direction. The length of the vector is its magnitude. Its direction is the direction of the vector.
The magnitude of the force is F=qvB.
According to Newton’s second law: F=ma, where m is the mass of the object, and a is its acceleration.
So, F=ma=qvB => a=F/m ,
a=qvB/m,
m in our case is the mass of an electron m=9.1x10^-31.
a= 1.60x10^-19C*2.40x10^6m/s*1.50x10^-5T/9