Question

when impact parameter is minimum

Answer 1

The impact parameter {\displaystyle b} is defined as the perpendicular distance between the path of a projectile and the center of a potential field {\displaystyle U(r)} created by an object that the projectile is approaching (see diagram). It is often referred to in nuclear physics (see Rutherford scattering) and in classical mechanics.

The impact parameter is related to the scattering angle {\displaystyle \theta } by[1]

{\displaystyle \theta =\pi -2b\int _{r_{\mathrm {min} }}^{\infty }{\frac {dr}{r^{2}{\sqrt {1-(b/r)^{2}-2U/mv_{\infty }^{2}}}}}}

where {\displaystyle v_{\infty }} is the velocity of the projectile when it is far from the center, and {\displaystyle r_{\mathrm {min} }} is its closest distance from the center.

Answer 2

When the impact parameter is minimum:

• We can define impact parameter as the perpendicular distance between the trail of a projectile and the center of a potential field.  

• The angle of deviation for the alpha particles becomes lesser as the value of the impact parameter increases. In contrast, when the impact parameter is minimum, force practiced by the alpha particle is very large and so, the scattering angle is large.  

Hope it helped........