Question

Select the correct statement(s) from the following. The path of a charged particle moving with an initial velocity u

• A. parallel to the uniform electrostatic field is a straight line.
• B. perpendicular to the uniform electrostatic field is a parabola.
• C. parallel to the uniform magnetic field is a helix with its axis parallel to the direction of B.
• D. perpendicular to the uniform magnetic field is a circle in a plane normal to the field.

Answer 1

Answer: (A), (B), (D)

Statements 1, 2, and 4 are correct.

Answer 2

The motion of a charged particle in uniform electric and magnetic fields is governed by the Lorentz force. Let's analyze each statement:

1. Parallel to E-field: Force F=qE is parallel to velocity u. Path is a straight line.
2. Perpendicular to E-field: Force F=qE is constant and perpendicular to initial velocity u. This is analogous to projectile motion, resulting in a parabolic path.
3. Parallel to B-field: Magnetic force F_B = q(u x B) = 0 because u is parallel to B. Path is a straight line, not a helix.
4. Perpendicular to B-field: Magnetic force F_B = quB is perpendicular to velocity u and acts as a centripetal force. Path is a circle in a plane normal to B.