A proton, a deuteron and α particle, whose kinetic energies are same, enter perpendicularly a uniform magnetic field. Compare the radii of their circular paths.

Let m₁, m₂, m₃ be the masses proton, deuteron and α-particle and v₁, v₂ and v₃ be their respective velocity.  

If m₁ = m,

then m₂ = 2m  and m₃ = 4m

Let q₁, q₂, q₃ be the charges on the proton, deuteron and α -particle respectively. If q₁ = q, then 

q₂ = q and q₃ = 2q