Question

An electron is projected with uniform velocity along the axis of a current carrying long solenoid. Which of the following is true?

• A. The electron will experience a force at ${45}^{\circ }$ to the axis and hence execute a helical path.
• B. The electron path will be circular about the axis.
• C. The electron will continue to move with uniform velocity along the axis of the solenoid
• D. The electron will be accelerated along the axis.

Answer 1

The correct option is C The electron will continue to move with uniform velocity along the axis of the solenoid

As we know that in a current carrying long solenoid the magnetic field is only inside the solenoid and parallel to the axis.

Therefore, when electron is projected with uniform velocity along the axis of a current carrying long solenoid it will experience a force due to the magnetic field which is given by,

$F=qvB\sin \theta$

Here, $\theta =0^{\circ }$ 𝑆𝑜, $F=0$

Hence the electron will continue to move with uniform velocity along the axis of the solenoid.

$\text{Final Answer}:$ (d)