Q55 / 75 · JEE Main 2026 (21 January Shift 1) · Physics

A current carrying solenoid is placed vertically and a particle of mass $m$ with charge $Q$ is released from rest. The particle moves along the axis of solenoid. If $g$ is acceleration due to gravity then the acceleration (a) of the charged particle will satisfy :

  • A
    $a>g$
  • B
    $0 < a < g$
  • C
    $a=0$
  • Correct answer
    D
    $a=g$

Solution

Inside a solenoid, magnetic field $\vec{B}$ is uniform and parallel to the axis.
Particle moves along the axis, so velocity $\vec{v}$ is parallel to $\vec{B}$.
Magnetic force $\vec{F} = Q(\vec{v} \times \vec{B}) = 0$ (since $\vec{v} \parallel \vec{B}$)
Only gravity acts on the particle.
Acceleration $a = g$

Hence, the correct answer is option: 'D'.

Relevant Questions