Question

If an α-particle collides head-on with a nucleus, what is its impact parameter?

(a) Zero

(b) Infinite

(c) 10^-10 m

(d) 10^10 m

This question was addressed to me by my school principal while I was bunking the class.

This intriguing question comes from Alpha-Particle Scattering and Rutherford’s Nuclear Model of Atom in section Atoms of Physics – Class 12

Answer 1

Correct choice is (a) Zero

Easy explanation: The perpendicular distance between the path of a projectile and the center of the potential field is the impact parameter. Therefore, for a head-on collision of the α-particle with a nucleus, the impact parameter is equal to zero.