Write a proportionality expression that represents the relationship between the magnetic force and the magnetic field strength.

The relationship between the magnetic force (F) and the magnetic field strength (B) is given by the equation F = qvBsinθ, where q is the charge of the particle, v is the velocity of the particle, and θ is the angle between the velocity and the magnetic field.

However, if we consider a scenario where a charged particle is moving perpendicular to the magnetic field (θ = 90°), the sinθ becomes 1 and the equation simplifies to F = qvB.

In this simplified scenario, the magnetic force is directly proportional to the magnetic field strength. This can be expressed as F ∝ B.

So, the proportionality expression that represents the relationship between the magnetic force and the magnetic field strength is F ∝ B.