Question

An electron as the alpha particle enter in a uniform magnetic field antiparallel to it. The magnetic field force acting on particle will be

• A. Maximum on $\alpha$-particle and zero on electron
• B. Maximum on electron and zero on $\alpha$-particle
• C. Zero on both particles.
• D. Minimum on electron and maximum on $\alpha$-particle

Answer 1

The correct option is C Zero on both particles.

$\text{Solution}:$

The magnetic force acting on the charged particle is given by :

$F=qvBsin\theta$

q is charged particle

v is the speed of charged particle

$\theta$ is the angle between velocity and magnetic field

An electron and an alpha particle enters in the uniform magnetic field anti parallel to it, then the angle between electron and magnetic field is 0 degrees and the angle between electron and magnetic field is 180 degrees.

Magnetic field for electron is :

sin(0)=0

sin(180)=0

So, the magnetic field force on the both particle will be 0.

$\text{Hence C is the correct option}$