In f=q(v X b), velocity is with respect to what?

[hackersatyam]

in the formula f=q(v X b)
velocity is with respect to what

[sahoo]

in the formula f=q(v X b)
velocity is with respect to what

Magnetic Field

[nishantrpai]

it is actually w.r.t something i.e., @rest but since magnetic field is genrally the only 1 which is @rest we take it as magnetic field

[sahoo]

Thanks for the Explanation!