Work Done By Magnetic Force Is Zero — the NEET Physics formula with its derivation, variables, validity constraints and worked solver.
Work Done by Magnetic Force Is Zero This formula applies to any charged particle moving with a constant velocity in a uniform magnetic field. Define work done (P) as the dot product of force ( F ) and displacement ( d ): P = F d . The magnetic force is given by the Lorentz force law: F = q( v B ). The cross product ( v B ) yields a vector perpendicular to both v and B . Therefore, the magnetic force F is always perpendicular to the velocity v ( F v ). Since work is the dot product of perpendicular vectors, the work done is zero: P = 0. The magnetic force F must be perpendicular to the velocity v ( F v). Confusing the magnetic force being zero with the work done being zero (the force is generally non-zero). Assuming the magnetic force does work because the particle is accelerating (acceleration is centripetal, not parallel to force). Believing that the work done depends on the magnitude of the magnetic field B .