A proton, an electron, a neutron, an `alpha`-particle and an unknown particle enter a region of magnetic field with equal momental. Figure shows paths (market 1 to 5) followed by these particles. Identify which path corresponds to which particle

Explanation

The particle going straight (path 3) must be a netron. You can check from`vecF=q(vecvxxvecB)` that particle deviating upwards are negatively charged and particles deviating down are positively charged.
Now `r=(p/(qB))impliesr prop 1/q`, as momentum is same for each particle.
`implies` Pat 4 and 5 correspond to proton and `alpha`- particle respectivley. Also 2 corresponds to electron as 4 corresponds to proton (Why)?
`implies` Unknown particle is negativley charged (obviously with charge more than that on electron), so it follows path of smaller radius.
`implies` Path 1 and path 2 correspond to unknown particle and electron respectively.