Concepts Of Physics MCQ Edition [Volume 2]PhysicsMagnetic Field
If a charged particle travels without acceleration in a region containing electric and magnetic fields,
Options
- AE must be equal to vB
- BE must be perpendicular to B
- Cv must be perpendicular to B
- Dv must be perpendicular to E
Correct answer
D. v must be perpendicular to E
Step-by-step solution
The Lorentz force on a charged particle is given by F = q( E + v B ) . For the particle to move without acceleration, the net force must be zero: q( E + v B ) = 0 E = -( v B ) = B v From the properties of the cross product, the vector E must be perpendicular to both B and v . Therefore, E B and v E . The magnitude of the electric field is E = vB , where is the angle between v and B . Thus, E is not necessarily equal to vB , and v is not necessarily perpendicular to B .