A charge is moving with velocity v, it enters a uniform magnetic field B. The direction of v is perpendicular to B. What is the path of the charge particle inside the magnetic field?
Correct answer: B. Circular
- A. Parabolic
- B. Circular
- C. Parallel to v
- D. Parallel to E
Explanation
The path of the charged particle inside the magnetic field is circular.The force acting on the charged particle is given by the Lorentz force:F = q(v × B) where q is the charge of the particle, v is its velocity, and B is the magnetic field.Since the velocity and magnetic field are perpendicular in this case, the force is perpendicular to both the velocity and magnetic field. This means that the force does not change the speed of the particle, but only its direction.The particle will therefore move in a circular path, with the magnetic field providing the centripetal force. The radius of the circle is given by:r = mv/qB where m is the mass of the particle.The direction of the circular motion is determined by the right-hand rule. If you point your fingers in the direction of the velocity, and curl them in the direction of the magnetic field, your thumb will point in the direction of the force.The path of the particle will be a helix if the velocity is not perpendicular to the magnetic field, but has a component parallel to the magnetic field. The helix will have a pitch equal to the component of the velocity parallel to the magnetic field.
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