Question

Which of the following particles will experience the maximum magnetic force (magnitude) when projected with the same velocity perpendicular to the magnetic field?

• A. Electron
• B. Proton
• C. He⁺
• D. Li⁺⁺

Answer 1

The Correct Option is D

The magnetic force on a charged particle is given by: 

F = qvB sinθ

Where θ = 90° for perpendicular projection ⇒ sinθ = 1

Thus, the force depends on the charge q when v and B are constant.

Comparing the charges:

Particle	Charge (q)
Electron	-e
Proton	+e
He+	+e
Li++	+2e

Since Li⁺⁺ has the highest charge magnitude (2e), it will experience the maximum force.

The particle that will experience maximum magnetic force is Li⁺⁺.

Correct option: (4) Li⁺⁺

Answer 2

The magnetic force on a charged particle moving in a magnetic field is given by the Lorentz force law: 
\(F=qvBsinθ\)

where q is the charge of the particle, v is its velocity, B is the magnetic field strength, and θ is the angle between the velocity and the magnetic field. 

Since all particles are moving perpendicular to the magnetic field, sinθ=1, so the force is directly proportional to the charge of the particle.

Electron: charge = −e; Proton: charge = +e; He⁺ (Helium ion): charge = +e (since it’s lost one electron); Li⁺⁺ (Lithium ion): charge = +2e (since it has lost two electrons). 

The particle with the largest charge will experience the greatest force. Since Li⁺⁺ has a charge of +2e, it will experience the maximum force.